The growth of CAE tools has followed the industry through a familiar progression of technologies, starting out on mainframes in the 1980’s. Then pre- and post-processing migrated to the desktop in the 90’s, while solving continued on HPC systems, especially for compute-intensive analysis. The 2000’s have seen a continuous shift to more solving on the desktop with bigger, faster, parallel systems being used for the biggest problems.
CAE tools are now being used by mainstream engineers rather than CAE specialists, so more engineers are now able to run larger and more complex models. Smaller models may still be run on the desktop, but HPC systems are still required for larger, more-accurate models. Another driver for increased compute power is automated workflows. Parameter sweeps for geometric changes or boundary conditions can mean that 10 or 20+ models may need to be computed. With a matrix of parameters, run counts can get even higher.
Automated workflows enable optimization, with systems searching through a complex design workspace often running hundreds of simulation models in the process. Multi Disciplinary Optimization (MDO) pushes the envelope on this technology, linking multiple analysis tools. HEEDs, ModeFrontier and ANSYS DesignXplorer are examples of tools in which runtimes can be drastically reduced by deploying HPC via the Rescale platform.
Water Pump Efficiency Optimization Process
A CAD tool can control many geometric parameters to automatically create new solid models for CFD analysis. With a lot of variables, design spaces can become huge, where even the best MDX search engines still needing to run perhaps 100 different CFD models to find a better design. If each water pump model is 10 million cells, it may converge in 24 hours on a 64 core on-premise HPC system. That’s still 100 days! (Too much for a real world engineering problem.) There are two ways to accelerate this with the Rescale ScaleX platform:
- Increase the core count per job (Running each on 256 cores may reduce runtime per point to 6 hours), or
- Run multiple jobs concurrently. Technically you could run all 100 points at once on the Rescale ScaleX platform, but most optimization search engines use the results from previous runs to guide the direction of new runs. Typically only 10 (or less) of the 100 points can be run concurrently. At 40 runs per day, the Rescale platform could still condense the timeline from 100 days to 2.5 days!
Bicycle Aerodynamics Analysis
Many bicycle magazines from the last two years contain reviews of a series of bicycle brands being compared in a wind tunnel. Companies will also try to emulate the process with CFD.
The manual workflow for this process:
- Build base CAD model
- Identify key geometric parameters
- Apply parametric variables to CAD model
- Export CAD model
- Create CFD mesh
- Solve for aerodynamics
- Post-process for drag
Then repeat 20 times for different yaw angles. Repetitive and exhausting.
Imagine an automated process where parametric CAD geometry is used to create new geometries followed by CFD to evaluate aerodynamic performance of the frame. The numerical computation becomes substantial, and even though the actual man-hours is reduced the elapsed time is still a problem.
Using the DOE functionality within the Rescale platform, all 20 models above could be run concurrently. It is a simple way for any company, including SMBs, to get instant scalability and power. Instead of a bicycle aero CFD model taking 24 hours on 16 desktop cores, you can use 196 fast cores on the Rescale platform to turn it around in 2 hours. In addition, you can run 20 models at once. The GANTT chart looks very different when the whole virtual wind tunnel CFD test can be completed in 24 hours instead of 20 days!
The need for faster, easily-accessible compute power is now greater than ever. How can companies really get the best from CAE tools when they are continuously stymied by limited resources? Project timelines planned using a GANTT chart can often show CFD project runtimes in days or weeks, a dominant part of the full project timeline.
This has been the accepted norm for many years. But now we can show you how the Rescale cloud platform can remove those roadblocks and condense project timelines!
Level the Playing Field!
Many engineering companies or consultants are cautious to accept work where a large investment in computer hardware is required. Now, with Rescale’s ScaleX cloud HPC platform, any company can deploy adequate resources for the most complex CAE calculations. This is a market-changing dynamic. In the past, the most successful engineering companies would deploy large on-premise HPC systems. Much of their value to their clients was the availability of those systems. Now any group can deploy large HPC resources on-demand using the Rescale platform!
This article was written by Adam Green.