### Best Practices for Running Computational Fluid Dynamics (CFD) Workloads on AWS

July 8, 2020

The scalable nature and variable demand of CFD workloads makes them well-suited for a cloud computing environment. Many of the AWS instance types, such as the compute family instance types, are designed to include support for this type of workload. AWS has network options that support extreme scalability and short turn-around time as necessary.

Fluid dynamics is the study of the motion of fluids, usually in the presence of an object. Typical fluid flows of interest to engineers and scientist include: flow in pipes, through engines, and around objects, such as buildings, automobiles, and airplanes. Computational fluid dynamics (CFD) is the study of these flows through computer simulation and modeling. CFD involves the solution of conservation equations (mass, momentum, energy, and others) in a finite domain.

A typical CFD simulation involves the following four steps.

1. Define the Geometry

In some cases, this step is simple, such as modeling flow in a duct. In other cases, this step involves complex components and moving parts, such as modeling a gas turbine engine. For many cases, the geometry creation is extremely time-consuming. The geometry step is graphics intensive and requires a capable graphics workstation, preferably with a Graphics Processing Unit (GPU). Often, the geometry is provided by a designer, but the CFD engineer must “clean” the geometry for input into the flow solver.

1. Generate the Mesh or Grid

Mesh generation is a critical step because computational accuracy is dependent on the size, cell location, and skewness of the cells. Mesh generation can be iterative with the solution, where fixes to the mesh are driven by an understanding of flow features and gradients in the solution. Meshing is frequently an interactive process and its elliptical nature generally requires a substantial amount of memory. Like geometry definition, generating a single mesh can take hours, days, weeks, and sometimes months.

1. Solve for the solution

For some solutions, tens of thousands of cores (processors) run over weeks to achieve a solution. Conversely, some jobs may run in just minutes when scaled out appropriately. There are choices for model equations depending on the desired solution fidelity. The Navier-Stokes equations form the basis of the solved equations for most fluid calculations. The addition of chemical reactions, liquid and gas multi-phase flows, and many other physical properties create increasing complexity. For example, increasing the fidelity of turbulence modeling is achieved with various approximate equation sets such as Reynolds Average Navier-Stokes (RANS), Large Eddy Simulation (LES), Delayed Detached Eddy Simulation (DDES), and Direct Numerical Simulation (DNS). These models typically do not change the fundamental computational characteristics or scaling of the simulation.

1. Post process through visualization

Examples of this step include the creation of images, video, and post processing of flow fields, such as creating total forces and moments. Similar to the geometry and mesh steps, this can be graphics and memory intensive CFD workloads that typically scale well on the cloud. Most codes rely on domain decomposition to distribute portions of the calculation to the compute nodes. A case can be run highly parallel to receive results in minutes, or large numbers of cases can run simultaneously as efficiently and cheaply as possible to allow the timely completion of all cases.

Why CFD on AWS?

AWS is a great place to run CFD cases. CFD workloads are typically MPI-based, tightly coupled workloads relying on a large number of cores across many nodes. Many of the AWS instance types, such as the compute family instance types, are designed to include support for this type of workload. AWS has network options that support extreme scalability and short turn-around time as necessary. Small CFD cases can be run on a single node, with a large number of cores, and do not require the use of multiple instances.

CFD workloads typically scale well on the cloud. Most codes rely on domain decomposition to distribute portions of the calculation to the compute nodes. A case can be run highly parallel to receive results in minutes, or large numbers of cases can run simultaneously as efficiently and cheaply as possible to allow the timely completion of all cases.

The cloud offers a quick way to deploy and turn around CFD w

orkloads at any scale without the need to own your own infrastructure. You can run jobs that once were in the realm of national labs or large industry. In just an hour or two, you can deploy CFD software, upload input files, launch compute nodes, and complete jobs on a large number of cores. When your job completes, results can be visualized and downloaded, and then all resources can be terminated – allowing you to only pay for what you use. If preferred, your results can be securely archived in cloud storage. Due to cloud scalability, you have the option to run multiple cases simultaneously with a dedicated cluster for each case.

The cloud accommodates the variable demand of CFD. Often, there is a need to run a large number of cases as quickly as possible. Situations can require a sudden burst of tens, to hundreds, to thousands of calculations immediately, and then perhaps noruns until the next cycle. The need to run a large number of cases could be for a preliminary design review, or perhaps a sweep of cases for the creation of a solution database. On the cloud, the cost is the same to run many jobs simultaneously, in parallel, as it is to run them serially, so you can get your data more quickly and at no extra cost. The cost savings in engineering time is an often forgotten part of cost analysis. Running in parallel can be an ideal solution for design optimization. On AWS, you can launch the cases you need when your case is ready, without waiting in a queue for available cluster resources.

Cloud computing is a strong choice for other CFD steps. You can easily launch a GPU instance, a high-memory instance, or a cluster of high-memory instances, to handle the geometry, meshing, and post-processing. With remote visualization software available to handle the display, you can manage the GPU instance running your post-processing visualization from any screen (laptop, desktop, web browser) as though you were working on a large workstation.

Read the full white paper to learn about best practices for running computational fluid dynamics (CFD) workloads on AWS and quick start tools.

Get started with running your CAE/CFD workloads now – fill the form and get a \$100 AWS credit!

## A Big Memory Nvidia GH200 Next to Your Desk: Closer Than You Think

February 22, 2024

Students of the microprocessor may recall that the original 8086/8088 processors did not have floating point units. The motherboard often had an extra socket for an optional 8087 math coprocessor. The math coprocessor ma Read more…

## IonQ Reports Advance on Path to Networked Quantum Computing

February 22, 2024

IonQ reported reaching a milestone in its efforts to use entangled photon-ion connectivity to scale its quantum computers. IonQ’s quantum computers are based on trapped ions which feature long coherence times and qubit Read more…

## Apple Rolls out Post Quantum Security for iOS

February 21, 2024

Think implementing so-called Post Quantum Cryptography (PQC) isn't important because quantum computers able to decrypt current RSA codes don’t yet exist? Not Apple. Today the consumer electronics giant started rolling Read more…

## GenAI Having Major Impact on Data Culture, Survey Says

February 21, 2024

While 2023 was the year of GenAI, the adoption rates for GenAI did not match expectations. Most organizations are continuing to invest in GenAI but are yet to derive any substantial value from it. However, the GenAI hyp Read more…

## QED-C Issues New Quantum Benchmarking Paper

February 20, 2024

The Quantum Economic Development Consortium last week released a new paper on benchmarking – Quantum Algorithm Exploration using Application-Oriented Performance Benchmarks – that builds on earlier work and is an eff Read more…

## AWS Solution Channel

### Deep-dive into Ansys Fluent performance on Ansys Gateway powered by AWS

Today, we’re going to deep-dive into the performance and associated cost of running computational fluid dynamics (CFD) simulations on AWS using Ansys Fluent through the Ansys Gateway powered by AWS (or just “Ansys Gateway” for the rest of this post). Read more…

## Atom Computing Reports Advance in Scaling Up Neutral Atom Qubit Arrays

February 15, 2024

The scale-up challenge facing quantum computing (QC) is daunting and varied. It’s commonly held that 1 million qubits (or more) will be needed to deliver practical fault tolerant QC. It’s also a varied challenge beca Read more…

## A Big Memory Nvidia GH200 Next to Your Desk: Closer Than You Think

February 22, 2024

Students of the microprocessor may recall that the original 8086/8088 processors did not have floating point units. The motherboard often had an extra socket fo Read more…

## Apple Rolls out Post Quantum Security for iOS

February 21, 2024

Think implementing so-called Post Quantum Cryptography (PQC) isn't important because quantum computers able to decrypt current RSA codes don’t yet exist? Not Read more…

## QED-C Issues New Quantum Benchmarking Paper

February 20, 2024

The Quantum Economic Development Consortium last week released a new paper on benchmarking – Quantum Algorithm Exploration using Application-Oriented Performa Read more…

## The Pulse of HPC: Tracking 4.5 Million Heartbeats of 3D Coronary Flow

February 15, 2024

Working in Duke University's Randles Lab, Cyrus Tanade, a National Science Foundation graduate student fellow and Ph.D. candidate in biomedical engineering, is Read more…

## It Doesn’t Get Much SWEETER: The Winter HPC Computing Festival in Corpus Christi

February 14, 2024

(Main Photo by Visit Corpus Christi CrowdRiff) Texas A&M University's High-Performance Research Computing (HPRC) team hosted the "SWEETER Winter Comput Read more…

## Q-Roundup: Diraq’s War Chest, DARPA’s Bet on Topological Qubits, Citi/Classiq Explore Optimization, WEF’s Quantum Blueprint

February 13, 2024

Yesterday, Australian start-up Diraq added \$15 million to its war chest (now \$120 million) to build a fault tolerant computer based on quantum dots. Last week D Read more…

## 2024 Winter Classic: Razor Thin Margins in HPL/HPCG

February 12, 2024

The first task for the 11 teams in the 2024 Winter Classic student cluster competition was to run and optimize the LINPACK and HPCG benchmarks. As usual, the Read more…

## 2024 Winter Classic: We’re Back!

February 9, 2024

The fourth edition of the Winter Classic Invitational Student Cluster Competition is up and running. This year, we have 11 teams of eager students representin Read more…

## CORNELL I-WAY DEMONSTRATION PITS PARASITE AGAINST VICTIM

October 6, 1995

Ithaca, NY --Visitors to this year's Supercomputing '95 (SC'95) conference will witness a life-and-death struggle between parasite and victim, using virtual Read more…

## SGI POWERS VIRTUAL OPERATING ROOM USED IN SURGEON TRAINING

October 6, 1995

Surgery simulations to date have largely been created through the development of dedicated applications requiring considerable programming and computer graphi Read more…

## U.S. Will Relax Export Restrictions on Supercomputers

October 6, 1995

New York, NY -- U.S. President Bill Clinton has announced that he will definitely relax restrictions on exports of high-performance computers, giving a boost Read more…

## Dutch HPC Center Will Have 20 GFlop, 76-Node SP2 Online by 1996

October 6, 1995

Amsterdam, the Netherlands -- SARA, (Stichting Academisch Rekencentrum Amsterdam), Academic Computing Services of Amsterdam recently announced that it has pur Read more…

## Cray Delivers J916 Compact Supercomputer to Solvay Chemical

October 6, 1995

Eagan, Minn. -- Cray Research Inc. has delivered a Cray J916 low-cost compact supercomputer and Cray's UniChem client/server computational chemistry software Read more…

## NEC Laboratory Reviews First Year of Cooperative Projects

October 6, 1995

Sankt Augustin, Germany -- NEC C&C (Computers and Communication) Research Laboratory at the GMD Technopark has wrapped up its first year of operation. Read more…

## Sun and Sybase Say SQL Server 11 Benchmarks at 4544.60 tpmC

October 6, 1995

Mountain View, Calif. -- Sun Microsystems, Inc. and Sybase, Inc. recently announced the first benchmark results for SQL Server 11. The result represents a n Read more…

## New Study Says Parallel Processing Market Will Reach \$14B in 1999

October 6, 1995

Mountain View, Calif. -- A study by the Palo Alto Management Group (PAMG) indicates the market for parallel processing systems will increase at more than 4 Read more…

## CORNELL I-WAY DEMONSTRATION PITS PARASITE AGAINST VICTIM

October 6, 1995

Ithaca, NY --Visitors to this year's Supercomputing '95 (SC'95) conference will witness a life-and-death struggle between parasite and victim, using virtual Read more…

## SGI POWERS VIRTUAL OPERATING ROOM USED IN SURGEON TRAINING

October 6, 1995

Surgery simulations to date have largely been created through the development of dedicated applications requiring considerable programming and computer graphi Read more…

## U.S. Will Relax Export Restrictions on Supercomputers

October 6, 1995

New York, NY -- U.S. President Bill Clinton has announced that he will definitely relax restrictions on exports of high-performance computers, giving a boost Read more…

## Dutch HPC Center Will Have 20 GFlop, 76-Node SP2 Online by 1996

October 6, 1995

Amsterdam, the Netherlands -- SARA, (Stichting Academisch Rekencentrum Amsterdam), Academic Computing Services of Amsterdam recently announced that it has pur Read more…

## Cray Delivers J916 Compact Supercomputer to Solvay Chemical

October 6, 1995

Eagan, Minn. -- Cray Research Inc. has delivered a Cray J916 low-cost compact supercomputer and Cray's UniChem client/server computational chemistry software Read more…

## NEC Laboratory Reviews First Year of Cooperative Projects

October 6, 1995

Sankt Augustin, Germany -- NEC C&C (Computers and Communication) Research Laboratory at the GMD Technopark has wrapped up its first year of operation. Read more…

## Sun and Sybase Say SQL Server 11 Benchmarks at 4544.60 tpmC

October 6, 1995

Mountain View, Calif. -- Sun Microsystems, Inc. and Sybase, Inc. recently announced the first benchmark results for SQL Server 11. The result represents a n Read more…

## New Study Says Parallel Processing Market Will Reach \$14B in 1999

October 6, 1995

Mountain View, Calif. -- A study by the Palo Alto Management Group (PAMG) indicates the market for parallel processing systems will increase at more than 4 Read more…