Cloud CFD: Advanced Simulation Tools for Complex Flow Equations Within the Cloud

Key Takeaways

  • What computational fluid dynamics tools are.

  • Exploring how these tools work.

  • The advantages of cloud CFD tools.

Wind tunnels testing airplanes

Before cloud CFD tools were available, 7-story high wind tunnels were used to test full-size airplanes

At the beginning of the aeronautical age, wind tunnels were invented to help designers develop heavier-than-air flying machines. The benefits of a wind tunnel were obvious; engineers could test the flow of air around the vehicles they were designing without having to build multiple full-sized production models for practical tests. Then, in the late 1950s, computer power matured enough for designers to begin experimenting with virtual modeling of the flow of fluid and gases. Today, this new technology has evolved into a design system known as computational fluid dynamics, or CFD, and its uses extend far beyond the needs of only aircraft design.

Engineers across a wide range of industries, from industrial equipment to aerospace, use CFD tools to predict the flow of gasses and liquids in relation to the products they design. Additionally, these tools help engineers by calculating velocities, temperatures, densities, and pressures of the gasses and liquids they are working with. But, just as the introduction of CFD tools replaced the use of wind tunnel testing in many applications, the tools themselves are now in need of an upgrade. As the amount and complexity of designs needing CFD modeling increases, designers are facing a shortage of computer resources to do the job and are turning to cloud software for answers. This article will examine these problems and how cloud CFD tools are poised to take designs to the next level.

What Are Computational Fluid Dynamics Tools? 

Computational fluid dynamics is a system of using numerical analysis and data structures to simulate fluid and gas flows for analysis and problem-solving during engineering design. CFD tools can help engineers develop 3D models to calculate the interactions between fluids or gasses and the boundary structures of the objects being designed. These calculations require extensive computing power and are essential for creating virtual environments to simulate patterns such as the airflow faced by aircraft during different phases of flight. With their capabilities, CFD tools are now considered an essential part of the overall mechanical design process.

Electronics development is also dependent on mechanical design for its associated hardware. For years, the traditional interaction between electrical CAD (ECAD) systems and mechanical CAD (MCAD) systems has been virtually non-existent or limited to simply fitting a circuit board into a system enclosure. Although that is still an essential part of design, there is so much more to the ECAD/MCAD relationship today than simply how a PCB will fit into a box. 

To illustrate this, let’s use the example of thermal problems. Today’s high-speed electronics generate more heat than their predecessors, and this heat and its dispersion must be accounted for during design. To accomplish this, designers need the ability to simulate the thermal properties of not just a circuit board and its heat-generating components, but also the entire system. These simulations will give designers the information they need for airflow design within the system to provide the necessary amount of cooling for the electronics within it, without having to create multiple prototypes for testing. Thankfully, the CFD simulation tools electronic design engineers need for these simulations are now available from EDA companies like Cadence Design Systems.

At Cadence, the future of ECAD and MCAD tools is now a reality with the introduction of CFD tools. With the merging of Pointwise and Numeca’s CFD technologies, Cadence is pleased to introduce the first industrial high-order solver in its Fidelity CFD tool suite. These tools are new to many electronics designers, so let’s take a look at what goes into them.

Cloud CFD tools used in aircraft design

Cloud CFD tools are essential to design, such as simulating airflow patterns around aircraft

How CFD Tools Work

There are three distinct phases of analysis used by CFD tools:

  1. Processing preparation: A computer model is generated for analysis based on the flow type and grid points are assigned to the body and boundary of the flow in a process called meshing.
  2. Computational: A high-order solver is used to analyze and solve flow problems.
  3. Post-processing: The computational results are compiled and displayed for the user through static or moving flow images, or tables and graphs.

The first phase of this analysis is preparing the data for processing by generating computer models, a process known as “meshing.” There are two different types of meshing that can be used—structured and unstructured:

  • Structured meshing: A defined array of grid points that adds efficiency to the algorithms used in the creation of the mesh. They can be challenging to generate for complex shapes, usually requiring multi-zone techniques that knit together several structured grids. Structured grids are generally more accurate than other types of meshing.
  • Unstructured meshing: This mesh consists of triangular grids that are not defined arrays of grid points, which have to be defined through some form of look-up table. Although unstructured grids mesh easily with complex geometric shapes, the CFD simulations they produce are not as accurate as structured meshes.

Most modern CFD simulations use a hybrid combination of structured and unstructured CFD meshing for greater efficiency and accuracy.

One of the problems encountered by engineers using CFD tools is the number of computer resources required for the work. As we initially stated, CFD systems require a lot of power, starting with the generation of the mesh. Because the mesh ultimately influences the accuracy and speed of the simulation, creating a high-quality mesh is one of the most critical factors of the CFD process. Meshing requires extensive computing power to create its high-quality models quickly and accurately. Then, once the mesh is complete, the solver steps in and uses the meshing to perform the actual computations for the simulation. This step also requires a great amount of computational power, especially when multiple solving algorithms are in play.

As you can see, the computational requirements for using CFD tools are large, and they can have an enormous impact on engineers trying to run the simulations they need. Fortunately, there is an answer available in the power and resources of cloud computing.

Cloud CFD tools at work in automotive design

The mesh for an automobile analysis in CFD

The Advantages of Using Cloud CFD Tools

The amount of computing power necessary to rapidly render results from a CFD analysis has typically required high-powered engineering workstations. The Fidelity CFD tool suite from Cadence is an example of how these systems rely on high-performance computing, or HPC CFD, to conduct their analysis. And, as flow simulations increase in complexity, the need for additional computing power will also continue to grow, posing a problem for engineers that don’t have access to high-performance hardware. As it has been said, “I don’t have a server farm in my garage, so what can I do?” This question is beginning to be asked by a great majority of engineers who see the value of cloud CFD simulations but don’t have access to the hardware they need to economically run them.

Here is where the power of cloud computing can make a big difference in the engineering product design workflow. With the power of the cloud, access to HPC CFD simulations is now available to all engineers who need to simulate fluid and gas flows in their designs. With a standard computer and an internet connection, designers can tap into the power of the cloud to handle the majority of the computing for their cloud CFD simulations. Even the most complex cloud CFD analysis can run in the background without tying up resources. The future of design rests in the ability to run complex simulations like CFD, and the future of CFD depends on the power of the cloud.

Leading electronics providers rely on Cadence products to optimize power, space, and energy needs for a wide variety of market applications. If you’re looking to learn more about our innovative solutions, talk to our team of experts or subscribe to our YouTube channel. To hear the latest CFD updates, subscribe to our newsletter or browse Cadence’s suite of CFD software, including Fidelity and Fidelity Pointwise.

About the Author

Cadence PCB solutions is a complete front to back design tool to enable fast and efficient product creation. Cadence enables users accurately shorten design cycles to hand off to manufacturing through modern, IPC-2581 industry standard.

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