Richard Szöke-Schuller | Blogs & Articles | SimScale Content Manager Engineering simulation in your browser Tue, 13 Aug 2024 05:23:27 +0000 en-US hourly 1 https://wordpress.org/?v=6.8.3 https://frontend-assets.simscale.com/media/2022/12/cropped-favicon-32x32.png Richard Szöke-Schuller | Blogs & Articles | SimScale Content Manager 32 32 Bolt Connectors: Simplifying Structural Analysis https://www.simscale.com/blog/bolt-connectors-simplifying-structural-analysis/ Fri, 07 Jun 2024 12:15:41 +0000 https://www.simscale.com/?p=92270 As engineers and designers strive to develop simulation-driven structural designs efficiently and accurately, it is important to...

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As engineers and designers strive to develop simulation-driven structural designs efficiently and accurately, it is important to minimize the simulation setup complexity and requirements in the simulation tool. This, in turn, helps save time and computational resources. Bolt connectors are one aspect of structural design that engineers tend to struggle with, especially due to their usually large number and corresponding mesh requirements. Some would rather not include them in their CAD model but still need to consider them in their simulations.

Accordingly, SimScale has introduced a new feature that simplifies the process of simulating bolt connectors. Users do not need to add bolt geometries to their CAD models anymore. Instead, the Bolt Connector feature from SimScale offers a straightforward, mesh-efficient, and user-friendly solution to simulate bolted assemblies by simply adding virtual bolts in position, thus ensuring accurate results without the need to model intricate bolt geometries.

Bolt connector feature in SimScale used on a flange with multiple bolts
Figure 1: Bolt connector representation in SimScale

The Challenge of Bolted Connections

Bolted connections are a fundamental aspect of structural design, used to join multiple components securely. Typical methods of including bolts in simulations involve creating detailed CAD models of each bolt, which can be tedious and computationally expensive, especially when dealing with numerous bolts. Engineers often find it impractical to include these bolt geometries in their CAD models due to the intricacies and extensive meshing requirements. This challenge has necessitated a more streamlined approach to simulate bolted connections accurately and efficiently.

Introducing Virtual Bolt Connectors from SimScale

SimScale’s Bolt Connectors feature is a simple yet effective feature that changes how engineers simulate bolted assemblies in structural analysis. Instead of modeling bolts as detailed solid geometries, this feature uses finite element (FE) beam approximations to represent the bolts. In other words, bolt connectors simply mimic physical bolts using beam formulations, and the relative translations and rotations of the connected entities are computed based on the defined bolt mechanical properties. Users can easily define a bolt connector item for every virtual bolt while ensuring that the assigned entities are coaxial.

The result is a reduction in setup complexity and meshing requirements, allowing for efficient and accurate simulations even with a coarser mesh. By simplifying the workflow and enabling easy application of bolt preload, this feature not only accelerates the design process but also ensures precise behavior modeling, making it an effective asset in structural analysis.

This approach offers several advantages that ensure efficient simulation of bolted assemblies:

  • Reduced Setup Complexity: Setting up simulations involving numerous bolts becomes straightforward. Engineers can quickly define bolted connections without the need for intricate modeling of each bolt.
  • Reduced Mesh Requirement: By approximating bolts as beam elements, the Bolt Connectors feature reduces the mesh density required for simulations. This reduction leads to faster computation times and lower memory usage, allowing engineers to focus on optimizing their designs rather than managing computational resources.
  • Accurate Behavior with Coarse Mesh: Despite using a coarser mesh, the Bolt Connectors feature ensures that the simulated behavior of bolted connections remains accurate. The FE beam approximations are designed to capture the essential mechanical properties of bolts, providing reliable results even with less detailed meshes.
  • Intuitive Workflow: SimScale’s user-friendly interface makes it easy to define and manage bolted connections. Engineers can intuitively assign virtual bolt connectors to their models, enhancing productivity and reducing the learning curve associated with complex simulation setups.
  • Accurate and Easy Assembly Handling: The Bolt Connectors feature simplifies the assembly of multiple components. Engineers can efficiently simulate the interactions between various parts, ensuring that the overall structural behavior is accurately represented.
  • Bolt Preload Without Additional Boundary Condition: Preloading bolts is a common practice to enhance the stability and strength of connections. The Bolt Connectors feature allows engineers to easily apply preload to bolts without requiring additional boundary conditions, streamlining the simulation process.

Practical Applications of Bolt Connectors

The Bolt Connectors feature can be applied to a wide range of engineering scenarios. Whether designing automotive components, aerospace structures, or industrial machinery, this tool enhances the efficiency and accuracy of simulations involving bolted connections.

  • Automotive Industry: Bolted connections are ubiquitous in the automotive industry, from chassis assemblies to engine components. Simulating these connections accurately is crucial for ensuring vehicle safety and performance. The Bolt Connectors feature enables automotive engineers to model bolted joints efficiently, reducing computational overhead and speeding up the design iteration process.
  • Industrial Machinery: Robust bolted connections are essential for durability and safety in heavy machinery and industrial equipment. The Bolt Connectors feature allows engineers to model these connections without compromising on simulation accuracy, facilitating the design of more resilient and reliable machinery.
  • Aerospace Engineering: Bolted connections in aircraft components must withstand extreme conditions and stresses. Using the Bolt Connectors feature, aerospace engineers can simulate these connections with high fidelity, ensuring that the structural integrity of the aircraft is maintained while optimizing for weight and performance.

Other use cases include construction applications, marine applications, oil & gas, power generation, and more.

A close up of a car engine showing its bolts in position
Figure 3: Bolts on a car engine (Credit: Erik Mclean, Pexels)

How to Apply Bolt Connectors in SimScale?

Consider an example involving the design of a large industrial frame structure with numerous bolted connections. Traditionally, the engineer would need to model each bolt in detail, resulting in a complex CAD model and a dense mesh. This approach not only increases setup time but also demands significant computational resources. By utilizing SimScale’s Bolt Connectors feature, the engineer can represent each bolt with an FE beam approximation.

To explain how to use this feature, we take a case of a pipe flange under the effect of bolt preload. For reference, Figure 3 shows what such a connection would look like.

A CAD model of a bolted connection in a pipe flange
Figure 4: A bolted connection in a pipe flange

To apply the bolt connector, we use an equivalent geometry without the actual bolt model (Figure 4). Here, the bolt connector is of type Bolt and nut.

On a SimScale workbench, a bolt Connector feature applied to a pipe flange with a “Bolt and nut” type
Figure 5: Bolt Connector feature applied to a pipe flange with a “Bolt and nut” type

Here’s how to apply the Bolt Connector to the model:

  1. Select the Bolt Connector attribute under Connectors.
  2. Select the desired bolt type: (in this case, it is Bolt and nut)
    • Bolt and nut: This is a virtual connection between a bolt head and nut location.
    • Screw: This is a virtual connection between a screw head location and a cylindrical surface representing a threaded section.
  3. Enter the diameter of the bolt shank.
  4. Set up the mechanical properties of the bolt connector:
    • Enter the Young’s modulus value that characterizes the bolt material’s stiffness.
    • Enter the Poisson’s ratio value that describes the compression or elongation of the bolt material transverse to axial strain. Poisson’s ratio can have a value within range from -1 to 0.5.
    • Enter the density of the bolt material. Density is the mass per unit volume.
  5. If the bolt has a preload, enable bolt preload by setting the toggle on to define the pretension within the virtual bolt.
    • Define the tension force applied to the bolt during installation.
  6. Choose the deformation behavior of the assigned entity. If the user selects “deformable”, the entity is allowed to deform without applying additional stiffness. Selecting “undeformable” leads to a rigid entity.
  7. Assign the face(s) for the bolt head and the threaded section.

The bolt connector feature can also be used for a screw-type of bolt, as shown in Figure 5 with a similar application process.

In SimScale workbench, a bolt Connector feature applied to a pipe flange with a “screw” type
Figure 6: Bolt Connector feature with a “screw” type

Such a model simplification reduces the mesh density, leading to faster simulations and lower memory usage. Even with a coarser mesh, the simulation can accurately capture the mechanical behavior of the bolted connections, providing reliable insights into the frame’s structural performance.

The intuitive workflow of SimScale further enhances productivity. The user can quickly define and adjust bolted connections, experiment with different configurations, and apply bolt preload effortlessly. The result is a more efficient design process, allowing the user to focus on optimizing the structure rather than managing complex simulations.

Check out the SimScale structural mechanics page for more information.

Set up your own cloud-native simulation via the web in minutes by creating an account on the SimScale platform. No installation, special hardware, or credit card is required.

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Structural Optimization for Simulation-Driven Design https://www.simscale.com/blog/structural-optimization-for-simulation-driven-design/ Thu, 06 Jun 2024 08:28:39 +0000 https://www.simscale.com/?p=92212 Structural optimization is a design method that ensures designs are strong, efficient, and cost-effective early in their design...

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Structural optimization is a design method that ensures designs are strong, efficient, and cost-effective early in their design cycle. Structures must be optimized for the best possible performance with the least material usage, reducing costs and environmental impact.

In industries like aerospace, automotive, and civil engineering, optimizing structures ensures safety, reliability, and sustainability. Yet, traditional methods of structural optimization can be time-consuming and resource-intensive. With cloud-native simulation, engineers can perform complex simulations more quickly and accurately than ever before, enabling a highly efficient and scalable simulation-driven design.

In this article, we will explain why structural optimization is important and how cloud-native solutions like SimScale help achieve that.

A simulation result of an electric motor bracket in SimScale with an overlaid mesh
Figure 1: An electric motor bracket design can be easily optimized based on simultaneous simulation runs of different design parameters in SimScale.

What is Structural Optimization?

Structural optimization is the process of designing structures to perform their intended functions most efficiently. It involves creating structures that sustain loads with minimal material use while maintaining strength and durability [1].

The goal is to achieve objectives such as:

  • Minimum weight
  • Maximum stiffness
  • Resistance to instability

This must be done while adhering to constraints like stress limits, displacement restrictions, and geometric boundaries. This involves several key elements and mathematical formulations.

Objective Function (\(f\)): Evaluates design quality, typically minimizing weight, displacement, stress, or cost.

Design Variable (\(x\)): Represents the design, such as geometry or material choice, and can be adjusted during optimization.

State Variable (\(y\)): Indicates the structure’s response, including displacement, stress, strain, or force.

Considering problems that have multiple-objective functions, this leads to a vector optimization problem:

minimize (\(f_1​(x,y),f_2​(x,y),…,f_l​​(x,y)\))

Achieving Pareto optimality involves using a weighted sum:

$$ \sum_{i=1}^l w_i f_i​(x,y) $$

Where \(w_i ≥ 0\) and \(\sum_{i=1}^l w_i = 1\)

In structural optimization, constraints are crucial in defining the limits within which the structure must perform. These constraints ensure the design meets necessary safety, performance, and practical requirements.

  1. Behavioral Constraints: On \(y\) written as \(g(y)≤0\)
  2. Design Constraints: On \(x\), written similarly
  3. Equilibrium Constraint: the equilibrium constraint is:

$$ K(x)u=F(x) $$

Where:

  • \(K(x)\) is the stiffness matrix, dependent on the design.
  • \(u\) is the displacement vector.
  • \(F(x)\) is the force vector, also design-dependent.

In continuous problems, this often translates to partial differential equations. When addressing nested structural optimization issues by creating a series of explicit first-order approximations, it is necessary to distinguish the objective function and constraint functions in relation to the design variables. This process is referred to as sensitivity analysis. Sensitivity analysis involves finding the derivatives (or sensitivities) of \(f\) and \(g\) with respect to \(x\) to understand how changes in design variables affect the objective and constraints.

Types of Structural Optimization

Here are some major types of structural optimization:

  • Sizing Optimization: Sizing optimization involves adjusting the dimensions of structural elements, such as the thickness of beams or the cross-sectional area of columns, to achieve the desired performance.
  • Shape Optimization: Shape optimization aims to improve the external contours of a structure to enhance its performance. This process involves modifying the shape of the structure to reduce stress concentrations, improve aerodynamics, or enhance aesthetic appeal.
  • Free-Shape Optimization: Free-shape optimization allows for the modification of both the internal and external boundaries of a structure without predefined constraints. This approach provides maximum flexibility in achieving the optimal shape and material distribution.
  • Topology Optimization: Topology optimization focuses on finding the best material distribution within a given design space. By determining the optimal layout of the material, engineers can create structures that are lightweight yet strong.

Why is Structural Optimization Important?

Efficiency and Performance

Structural optimization is crucial for improving efficiency and performance in engineering projects. It minimizes weight and material usage, which directly reduces costs.
Additionally, it enhances structural performance by increasing stiffness and stability. This leads to more reliable and cost-effective designs.

Sustainability

Structural optimization contributes to more sustainable engineering practices by optimizing material use and reducing waste. It makes manufacturing processes more eco-friendly by lowering the environmental impact and promoting resource efficiency.

Innovation

Structural optimization, especially through cloud-native simulation, enables the creation of complex and efficient designs that would be unattainable with traditional methods.

Role of Engineering Simulation in Structural Optimization

Engineering simulation plays a pivotal role in structural optimization by providing accurate, predictive models that help engineers test and refine their designs before building physical prototypes. Finite Element Analysis (FEA) allows for the analysis of complex structures under various conditions, ensuring that the final design is both efficient and robust.

Engineers use simulation because it offers significant advantages over traditional methods. Unlike manual calculations and empirical testing, simulation can handle intricate designs and diverse scenarios with precision and speed.

Furthermore, simulation enables engineers to explore multiple design iterations quickly. Traditional methods often involve lengthy trial-and-error processes, while simulation streamlines these steps by providing immediate feedback on design changes.

Advancements with SimScale Cloud-Native Simulation

SimScale is a cloud-native simulation platform that integrates a complete engineering simulation workflow directly into your web browser. It makes advanced structural analysis both technically and economically feasible for any organization.

SimScale is user-friendly, requires no special hardware, offers limitless scalability, and is cost-effective for both individual users and large organizations. Additionally, it provides best-in-class real-time support and collaboration.

SimScale integrates seamlessly with Code_Aster for structural analysis. Code_Aster is a state-of-the-art and intensively validated open-source FEA solver developed by EDF in France. It allows companies to perform advanced FEA simulations efficiently, leveraging cloud computing power to handle the demanding nature of these tasks.

Based and deformed geometry analysis of the Praelong Dam using Code_Aster
Figure 2: The integration of Code_Aster and SimScale enables advanced FEA simulations in the cloud.

SimScale Applications for Structural Optimization

SimScale offers powerful tools for structural optimization to analyze and refine engineering designs efficiently. Here are some notable examples of structural optimization in SimScale.

1. Vibration Analysis Of an Electric Motor Bracket

Let’s talk about an example of vibration analysis of an electric motor bracket. In this case, six different bracket designs were evaluated to determine their eigenfrequencies and structural performance. The goal was to identify the optimal design that minimized vibration and maximized stability.

Using SimScale, engineers conducted simultaneous simulations of all six designs, allowing for a comprehensive comparison in a fraction of the time it would take using traditional methods.

Six electric motor bracket designs overlaid on a graph showing a modal analysis of their vibration for structural optimization
Figure 3: Electric motor bracket vibration analysis – Correlation between design variations and first eigenfrequency

The platform’s cloud-native capabilities meant that extensive computational resources were available on demand. Each design’s first eigenfrequency was plotted against the shaft speed, revealing which configurations were most effective at mitigating vibration issues.

2. Globe Valve Shape Optimization through SimScale

Using tools like SimScale and CAESES®, Gemü’s engineering team employed simulation and optimization to enhance valve performance across various industries. The workflow involved importing CAD geometry into SimScale, running flow simulations with a 1 bar pressure drop, and utilizing CAESES for design experiments.

The focus of the study was the optimization of the GEMÜ 534 globe valve, which is commonly used in industries such as water treatment, chemical processing, and power plants. Traditional CAD tools often struggle with complex geometries and optimization, making CAESES essential for handling sensitive geometric relationships.

Comparative analysis of globe valve performance using three CAD variants after undergoing structural optimization
Figure 4: Comparative analysis of globe valve performance using three CAD variants after undergoing shape optimization

The workflow includes parameterizing the CAD model, defining simulation conditions, and running CFD simulations on various design variants. Initial optimization led to an increase in the Kv value from 54.93 to 58.49, with further refinements achieving an 8.3% improvement.

Ready to optimize your designs with SimScale’s powerful tools? Start simulating by clicking below or request a demo and see how SimScale can enhance your engineering projects with precision and efficiency.

Set up your own cloud-native simulation via the web in minutes by creating an account on the SimScale platform. No installation, special hardware, or credit card is required.

References

  • Christensen, P.W. & Klarbring, A. (2009) An Introduction to Structural Optimization. Springer Dordrecht. DOI: 10.1007/978-1-4020-8666-3

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SimScale’s Summer Product Update https://www.simscale.com/blog/simscales-summer-product-update/ Fri, 14 Aug 2020 13:44:53 +0000 https://www.simscale.com/?p=32460 While the temperature has been heating up this summer, so are things on the SimScale Platform! Since our last product update...

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While the temperature has been heating up this summer, so are things on the SimScale Platform! Since our last product update announcement, we’ve been working hard to implement what our users are asking for, to make SimScale the very best it can be. In this release blog post, we will cover seven updates users can try themselves, right away. 

Update One: Cool Changes to CHT Analysis 

This implementation consists of a completely new version of the conjugate heat transfer (CHT) solver. To find out more about the technical details of this, download and read the white paper below.


The decisive difference, compared to the old solution, is that the new algorithm solves the energy equation, which calculates the temperature in the solids and the flow regions, in the same loop for all parts. This speeds up convergence massively—often within a couple of hundred iterations—and additionally allows for a more efficient parallel computation.

cht update simscale platform image showing convergence comparison electronics cooling
Convergence comparison for an LED natural convection analysis

The solver already supports the main functionality of our current CHT analysis type. There are a few exceptions that are not yet available, but are, of course, on the short- or mid-term roadmap. We added the new solution as a new analysis type in order to only expose the options that are already supported in the user interface. Hence, they are quite easy to identify. To give you a concise overview:

  • Buoyancy effects are calculated based on the Boussinesq approximation
  • One flow region only
  • Gauge pressure is set by default to 0
  • Anisotropic conductivity is not supported
  • Electronic components like thermal interface materials or power networks are not yet available

You can create a CHT simulation based on the new solver by selecting “Conjugate Heat Transfer v2.0” below the current “Conjugate Heat Transfer” in the analysis type widget. In case you can not see the option as displayed below, please reach out to our support!

cht v2.0 in the simscale platform
Find a new analysis type “Conjugate Heat Transfer v2.0” in the analysis type selection widget.

Important notes:

  • The new solver is based on a special meshing technique that ensures the mesh interfaces are conformal between all parts. That means that old meshes created within the current CHT analysis type are not usable in the new analysis type and vice versa and are therefore also not available for assignment.
  • The conformal meshing requires that you imprint your geometry before using it in the new analysis type.

Update Two: Boundary Layer Mesh Control

Within SimScale, it is now possible to control the boundary layer mesh while still fully automating the mesh generation:

view of boundary layer mesh control
New controls for automatically generated boundary layers

Update Three: Additional Units

There are additional input units added, rather than the more limited SI units we had previously. More to come!


Update Four: Better Browser Tab Indication 

For users that utilize our new collaboration features, the browser tab now indicates when someone requests to take over the edit mode.

visualization of browser tab indication

Being able to collaborate on a single simulation project in SimScale with multiple users is a well-used and popular feature (available as part of the SimScale Team plan or when interacting with support). One of the most reported issues with real-time collaboration has now been resolved. From now on, any user will notice if a collaborator would like to take over their project by looking at the browser tab. A notification icon and a change of the tab title will alert you of a takeover request by another user.


Update Five: FEA Setup Validation

This update includes new FEA validation rules. For most of the structural analysis types (static, dynamic, harmonic, thermal, and thermomechanical Analysis), new validation rules have been implemented that either warn the user or prevent the run creation in case an under-constrained setup is being recognized.

For example, a static analysis with only fixations and no loads or vice-versa, an analysis with only loads and no constraints will prompt an error message before actually starting a run.


Update Six: Expanding Our Import & Export Capabilities 

Additional outputs for incompressible lattice Boltzmann method (LBM) simulations are now available for users, including friction velocity and surface normals. Friction velocity is an important indicator of aerodynamics to investigate flow separation points on the surface. It allows for the computation of derived quantities of interest with a local post-processing environment (friction forces). The surface normals have been added as an additional field as they are required for any local analysis. They are consistent with the flow conditions from the LBM solution in contrast to normals derived from the geometry in the post-processing tool, which might have flipped orientations.

Additionally, mesh export for pedestrian wind comfort (PWC) now also shows cell size as a result field. From now on, every pedestrian wind comfort analysis will automatically save the computational grid as an additional result for each of the computed wind directions and the cell size field makes it easier to visually inspect the mesh resolution throughout the whole computational domain.

pedestrian wind comfort analysis cell size simscale
Cell size in meters visualized on a cutting plane through the mesh of an urban city model

Update Seven: Multi-Phase Velocity Limiter 

Last but not least, we added a velocity limiter for multiphase simulations. The velocity limiter for multiphase is a numerical aid to stabilize the flow in case high velocities appear locally during initial phases or due to numerical artifacts close to the free surface.

That’s all, for now! Stay cool, and more importantly stay tuned for more updates coming soon! 


To read about all of our 2020 updates, check out these resources: 

Set up your own simulation via the web in minutes by creating an account on the cloud-based SimScale platform. No installation, special hardware or credit card is required.

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SimScale Enables Compliance with City of London Wind Microclimate Guidelines for New Developments https://www.simscale.com/blog/london-wind-microclimate-guidelines/ Tue, 07 Apr 2020 00:00:50 +0000 https://www.simscale.com/?p=25342 Urban microclimates affect more than the hustle and bustle of busy high streets. They can dictate everything from building energy...

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Urban microclimates affect more than the hustle and bustle of busy high streets. They can dictate everything from building energy performance and the implementation of renewable energy technologies to necessary safety precautions for pedestrians and cyclists. Last year, the City of London reassessed and reclassified their acceptable microclimate conditions, in an effort to prevent future builds causing wind discomfort to tourists and city dwellers alike. 

Southwest (SE) wind velocity map at the pedestrian level around the London Bridge area (Source: SimScale simulation using AccuCities CAD model).

London’s new developmental guidelines aimed to formalize a very detailed and standardized framework for wind comfort assessment for the City. With that, a high-quality standard, reproducibility, and comparability of all wind studies is ensured. Additionally, the requirement of doing wind studies for all new developments higher than 25m ensures that pedestrian comfort and safety are virtually always being assessed. Finally, this new guide is the first time that cyclists have specifically been taken into consideration in such an all-encompassing standardization.

channeling and downdraft effect
Channeling (left) and downdraft effect (right).

From commercial skyscrapers to residential high rises, wind can be accelerated either through narrow channels between these structures or, more concerning for passersby, from being accelerated downward towards the ground through downdraft effect.

bridgewater place in leeds UK
Bridgewater Place (left), Leeds, UK.

In 2011 in Leeds, a northern UK city, accelerated wind speeds caused by the 110m-tall Bridgewater Place office and apartment building caused a truck to roll over, killing a pedestrian. This, along with other incidents, in turn, prompted a country-wide reconsideration towards wind design; with London prevailing as the biggest offender.

The Wind Microclimate Guidelines for Developments in the City of London report the required investigations to assess a proposed structure’s impact on the surrounding environment, concerning the comfort and safety of nearby pedestrians and cyclists.

Maintaining Wind Comfort in the City of London

In the City of London specifically, many skyscrapers have recently become a part of its skyline, and plans for at least 13 more are in the works to be built by 2026. One infamous tower to note, “The Walkie-Talkie” building at 20 Fenchurch Street, is a prime example of why these new guidelines have come to fruition. Existing as a safety hazard to pedestrians below, this building, among others, prompted more comprehensive safety assessments of how intended structures will affect people on ground-level, with an increased evaluation of streets and the surrounding area using detailed scale models in wind tunnels and computer-aided engineering (CAE) simulations. These evaluations essentially aim to maintain pedestrian wind comfort while urban development projects continue. 

downdraft and cornering wind effects against the News Building facade
Wind velocity streamlines from southwest (SE) direction showing downdraft and cornering wind effects against The News Building facade (Source: SimScale simulation using AccuCities CAD model).

How Is Pedestrian Wind Comfort Assessed?

In order to evaluate the wind in London for existing or future developments, three components must be combined:

  1. Historical meteorological data close to the location of the building to get representative/typical wind conditions.
  2. Local wind conditions which are influenced by the building itself and its surroundings.
  3. Comfort criteria that relate local wind speeds to actual subjective “wind comfort”.
downdraft effect against the shard facade  london wind microclimate
Wind velocity streamlines from southwest (SE) direction showing downdraft effect against The Shard facade (The highest skyscraper in London) (Source: SimScale simulation using AccuCities CAD model).

Once this information is determined, engineers must evaluate the proposed building design against the environmental conditions of the area, while conforming to the comfort criteria standard. 

Real-world Simulation: Wind Tunnel Assessment 

Wind tunnel testing was first used for evaluating the aerodynamics of airplanes in WW2. It was only later that wind tunnel studies were undertaken for evaluating the effects of wind on man-made structures when buildings became tall enough to present large surfaces to the wind, and the resulting forces had to be resisted by the building’s inner structure. Calculating such forces was required before building codes, wind comfort codes, or wind microclimate codes existed; and were used to basically specify the required strength of the buildings to withstand against the external wind forces. 

These new microclimate guidelines apply to buildings that are above the average height of surrounding buildings (more generally, 25m above in the City of London). Though wind tunnel evaluation is a tried and tested methodology for assessing London’s famous skyline, any building that exceeds 50m height must look at additional or alternative methods of investigation. CFD is a viable additional method of assessing these wind conditions. 

Online Simulation: CFD Evaluation

Within these new guidelines, computational fluid dynamics (CFD) is among one of the recommended approaches for evaluating buildings over a certain height (more specifically, 25m or higher). This standard urges engineers to address wind impact early in the design process, as well as incorporate multiple scenarios to be studied before drawing actionable conclusions. 

annual london lddc wind comfort map
Annual London LDDC wind comfort map around the London Bridge area. (Source: SimScale simulation using AccuCities CAD model)
london lddc microclimate guideline wind comfort and risk criteria
London LDDC wind comfort and risk criteria

As a cost-effective and cloud-based CFD platform, SimScale is supporting UK based architects, engineers, and designers that must adhere to these new rules and contribute to a safer London. 

SimScale Solution: CFD for The Wind Microclimate Guidelines for Developments in the City of London 

Here at SimScale, we’ve added a specific feature dedicated to wind comfort evaluation for developments in the City of London which is in accordance with the official guidelines. In order to cut down on design time and maximize efficiency, this feature is accessible via an extremely streamlined and easy-to-use workflow. This new London wind microclimate feature also allows architects and urban planners, besides wind engineers, to get valuable insights on wind microclimate impacts, early in the design process. Using Pedestrian Wind Comfort Analysis through SimScale, users are now able to:

  • Directly use the exact wind statistics data as defined in the guidelines. 
  • Run the wind analysis for up to 36 wind directions.
  • Compute pedestrian wind comfort and safety according to the London LDDC criteria on an annual, seasonal, and also  “worst season” scenario—in a single analysis.
  • Analyze the wind flow patterns around the proposed buildings using streamlines, velocity vectors, and much more for each of the 36 wind directions.
Wind velocity streamlines from southwest (SW) direction through the news building and the Shard.
Wind velocity streamlines from southwest (SW) direction through the news building and the Shard together with pedestrian wind comfort criteria (Source: SimScale simulation using AccuCities CAD model)

“SimScale’s workflow makes it possible for engineers to comply with the CFD requirements of the Wind Microclimate Guidelines for Developments in the City of London quickly and easily,” said Richard Szoeke-Schuller, product manager at SimScale. “Developers are guided by SimScale’s workflow to enter parameters and perform needed calculations. Because SimScale is cloud-based, multiple simulation scenarios can be run in parallel. All of this not only saves time, but allows for design validation to happen early and iteratively.” – Richard Szöke-Schuller, SimScale Product Manager 

richard szöke-schuller simscale
Richard Szöke-Schuller, Product Manager

Want to Learn More About Pedestrian Wind Comfort with SimScale? 


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8 SimScale Updates to Kick Off 2020 I Product Release https://www.simscale.com/blog/simscale-updates-2020/ Wed, 05 Feb 2020 15:14:37 +0000 https://www.simscale.com/?p=23554 Read about our latest feature updates from January 2020, happening at SimScale. From the addition of weather data to scientific...

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A new year brings a new list of resolutions, new obstacles to overcome, and new goals to achieve. Here at SimScale, it’s no different. A new year brings new product features and updates aimed to help our professional users get even more out of our cloud-based platform. In this article, we will discuss the updates we’ve released so far in 2020.

Update 1: Weather Data Import

Last year, we rolled out a lot of improvements to our wind comfort analysis module. In 2020, our plan is to continue to invest in wind comfort analysis. Now at SimScale, wind data, provided by meteoblue, can be imported automatically. No longer do users need to gather and upload wind rose information manually, it is now possible with just the click of a mouse.

Update 2: 36 Wind Directions

Up until now, users were able to input wind data for up to 16 wind directions. For some wind comfort standards, a higher resolution is required. Due to this, SimScale now allows up to 36 wind directions to be evaluated simultaneously.

Created using Google Maps

Update 3: New Post-Processing Interface for PWC Result Data

As of January 2020, SimScale has released a completely reworked interface for statistical Pedestrian Wind Comfort data. What’s more, over the coming weeks, the post-processing interface for all other analysis types will also be updated step-by-step.

post processing interface update

Update 4: NEN 8100 Wind Standard Calculation

As an additional effort to invest in wind comfort analysis, the full calculation for the NEN 8100 wind comfort standard is now available to users. This allows the direct import of the data sets from the official NPR 6097 program to be computed and presented as NEN 8100 comfort and safety plots separately as per the standard.

nen 8100 product update

Update 5: Zoom to Mouse

When zooming in the post-processor, the zoom target is now defined by the mouse cursor position. With this update, the behavior in post-processing is aligned with the pre-processing viewer experience.

Update 6: Point Selection via Click on the Model

When having to define a rotation center point within the SimScale platform, so far the coordinates needed to be put in manually. This update allows the selection of a point via a click on the model. No more pesky coordinates! (However, the option still exists, if needed).

selection_tool_2

Update 7: Multiphase Numerics Improvements

For multiphase simulations, we have added the following updates:

  • Relaxation factor for U
  • Relaxation factor for p_rgh (pressure field)
  • Relaxation factor alpha (volume fraction)
  • Number of outer correctors to numerics settings

This enhancement will help simulations run and converge better than ever before, with additional iterations and increased accuracy!

Multi-Phase Numerics Improvements
You can now see the evolution of all the fluid variables along with the iterations of a multiphase simulation and have complete control of their convergence.

Update 8: Scientific Notation for Value Inputs

All numeric input fields across all settings panels now support scientific notation. A value can be input either in decimal or scientific form. With the update, default representation mode when a field is not focused on will be the scientific form.

Scientific Notation for Value Inputs

Stay tuned for more updates for 2020!

Other Recent Product Update Blogs from SimScale:

Some images used in this article were created using Google Maps.

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