What is CFD?

Computational Fluid Dynamics commonly referred to as CFD allows engineers to predict fluid flow, heat transfer, mass transfer, and chemical reactions in three dimensions. These phenomena are numerically modeled by a set of partial differential equations called the Navier-Stokes equations.

How did CFD evolve?

In 1960s, CFD was introduced as a specialized engineering tool in the aerospace and defense industries in aerodynamic and hydrodynamic processes. In 1970s CFD expanded its root into the automotive industries in the fluid transmission system. In consequent years, CFD was widely accepted as a common tool in other commercial applications such as semiconductor, MEMS processing and Biomedical etc.

Recently, CFD is integrated into the Computer Aided Design (CAD) environment to perform fluid flow analysis and design analysis in the initial stages of product / process development. With simplification and better integration with the CAD interface, the traditional professionals only CFD is making its way into the mainstream Computer Aided Engineering (CAE) market.

What are the uses and benefits of CFD?

Companies use CFD as a strategic competitive advantage tool to leverage new product and process development, existing process optimization and cost reduction.

The key benefits of CFD are:

Cost:

Developing physical prototypes are extremely costly to build and test. CFD is a valuable tool to assess different designs, perform parametric studies and virtual prototype each design before actual fabrication

Time-to Market: 

CFD identifies the flow and design problem early in the design cycle and reduces the design and development time without compromising on the quality.

Competitive Product Design:

CFD analysis is a significant tool to evaluate multiple what-if scenarios and to iterate the process virtually upon improvement till the optimal design is achieved.

What are the steps in CFD?

The three basic steps CFD modeling are pre-processing, solver, post-processing.

Pre-processing:

The first and foremost step in CFD simulation is creating and gridding a geometry model.  The size and type of mesh elements depends on geometry of model and physical phenomena of interest. While our general purpose pre-processor CFD-GEOM grids the geometry quickly and efficiently, our next generation meshing tool CFD-VisCART is powerful in handling complex geometries such as underhood thermal management studies. Both of these pre-processors support CAD files and SAT, IGES, NASTRAN, PLOT3D, STL files and meshed geometry files such as ICEM-CFD and GAMBIT.  Whether the geometry is an imported CAD model or a meshed geometry, the pre-processors discretize the solution field and locate boundary and volume conditions.

Solver and Solution Generation:

The meshed file is imported into the CFD solver for problem set-up and solution generation. ESI Group has three key solvers for specific simulation needs: CFD-ACE+, CFD-FASTRAN, CFD-CADalyzer.  CFD-ACE+ is a multiphysics and multidisciplinary CFD code that ensure the most efficient operation, both in terms of physics interaction and numerical stability. CFD-FASTRAN is the leading commercial CFD software for aerodynamic and aerothermodynamic applications. It employs state-of-the-art multiple moving body capability for simulating most complex aerospace problems. CFD-CADalyzer is a Coupled Design Analysis CDA tool. It lets design engineers to rapidly and accurately validate their designs earlier in the product development cycle.

Post-processing:

Once the simulation is completed, the native simulation file is imported into the post-processing software which allows the user to visualize and analyze the results. ESI group post processor CFD-VIEW provides an easy-to-use and interactive environment with many graphics tools to visualize the flow physics, animate transient data sets, as well as extract data relevant to engineering design. CFD-VIEW also supports Tecplot files Ensight files etc.

What is Multiphysics

Multiphysics is the process of simulating the effects of two or more interacting physical Phenomena. Multiphysics typically involve solving coupled systems of partial differential equations. From catheters to semiconductor processing and from microphones to MEMS (microelectromechanical systems), many of today’s design challenges require evaluating more than one aspect of physics that are coupled, and often mutually dependent, phenomena.

The more common and mature analyses of multi physics include fluid–structure, thermal–mechanical, and electric–thermal interactions. In fluid–structure interaction, fluid flow exerts pressure on a solid structure, which causes it to deform such that it perturbs the initial flow. Example: Deformation of an aircraft wing during flight. In Thermal– mechanical many structures change their shapes and material properties as a result of a temperature increase or decrease. Example: Transient heating of an automotive exhaust manifold due to flow of the internal hot exhaust gas stream. In Electric-thermal interaction, current flowing in a conductor generates resistive heating. Example: Heat conduction in dielectric and semiconductor material.