# What Is Computational Fluid Dynamics (CFD)? How Is It Applied? What Are The Advantages?

## WHAT IS COMPUTATIONAL FLUID DYNAMICS?

**Computational Fluid Dynamics (CFD)** is the science of predicting fluid flow, heat transfer, chemical reactions, and related phenomena by solving the mathematical equations which govern these processes.

CFD, also sometimes referred to as *fluid flow simulation*, is a numerical computer simulation that permits the fluid flow around or through any object, so the impact on that object can be analysed in detail.

When using this simulation during design, an engineer can establish early on whether their product will conform to a client’s requirements.

The accuracy of modern CFD methods significantly increases the level of design insight available to engineers throughout the design process. Applying CFD generally means that fewer physical prototypes will have to be built during product development, and that means less prototype testing will have to be carried out. *Time-to-market* and *cost-to-market* is subsequently decreased.

Technical risk and possible loss of investment is also greatly reduced when developing thermal- and fluid-based products with CFD software.

## ADVANTAGES OF CFD

**Gain insight**into systems that might be difficult to test through experimentation.**Foresee performance and optimise the design accordingly.**Without modifying or installing real systems, CFD simulation can forecast which changes in design are most vital for improving performance.**Predict**mass flow rates, pressure drops, heat transfer rates, and fluid dynamic forces such as lift, drag and pitching moments.**Lower costs**by using CFD simulations instead of physical experimentation to retrieve essential engineering data.**Introduce engineering data early in the design process.**Simulations can be executed in a far shorter period of time when compared to physical testing.**Simulate real conditions.**Some flow and heat transfer processes cannot be physically tested, e.g. hypersonic flow. But CFD provides the ability to theoretically simulate any physical condition.**Simulate ideal conditions.**CFD permits great control over the physical processes, and offers the ability to isolate specific phenomena for study.**Examine data from a large number of locations.**Physical testing limits the number of locations that can be examined in the system. CFD permits the examination of a large number of locations in the area of interest, and yields a comprehensive set of flow parameters for examination.

## APPLICATIONS OF CFD

Computational Fluid Dynamics can be applied to different industries for different analytical capabilities. Some of the prime industries where CFD or fluid flow simulation is frequently used, are:

- Aeronautics
- Automotive
- Building HVAC
- Chemical
- Power Generation
- Manufacturing
- Process Engineering
- Product Design + Optimisation
- Oil + Gas Industry
- Turbo Machinery, etc.

## LIMITATIONS OF CFD

- PHYSICAL MODELS
- NUMERICAL ERRORS
- BOUNDARY CONDITIONS

– CFD relies upon physical models of real world processes.

– CFD solutions can only be as accurate as the physical models.

– Solving equations on a machine also introduces numerical errors, e.g.

– Round-off error (due to finite word size available on computer, round-off errors will always exist).

– Truncation error (due to approximations in the numerical models).

– Similar to physical models.

– The accuracy of the CFD solution is only as good as the initial boundary conditions provided to the numerical model.

## WHAT IS COMPUTATIONAL FLUID DYNAMICS?

**Computational Fluid Dynamics (CFD)** is the science of predicting fluid flow, heat transfer, chemical reactions, and related phenomena by solving the mathematical equations which govern these processes.

CFD, also sometimes referred to as *fluid flow simulation*, is a numerical computer simulation that permits the fluid flow around or through any object, so the impact on that object can be analysed in detail.

When using this simulation during design, an engineer can establish early on whether their product will conform to a client’s requirements.

The accuracy of modern CFD methods significantly increases the level of design insight available to engineers throughout the design process. Applying CFD generally means that fewer physical prototypes will have to be built during product development, and that means less prototype testing will have to be carried out. *Time-to-market* and *cost-to-market* is subsequently decreased.

Due to the capabilities of CFD software, technical risk and possible loss of investment is greatly reduced when developing thermal- and fluid-based products.

## ADVANTAGES OF CFD

- Gain insight into systems that might be difficult to test through experimentation.
- Foresee performance and optimise the design accordingly. Without modifying or installing real systems, CFD simulation can forecast which changes in design are most vital for improving performance.
- Predict mass flow rates, pressure drops, heat transfer rates, and fluid dynamic forces such as lift, drag and pitching moments.
- Lower costs by using CFD simulations instead of physical experimentation to retrieve essential engineering data.
- Introduce engineering data early in the design process. Simulations can be executed in a far shorter period of time when compared to physical testing.
- Simulate real conditions. Some flow and heat transfer processes cannot be tested, e.g. hypersonic flow. But CFD provides the ability to theoretically simulate any physical condition.
- Simulate ideal conditions. CFD permits great control over the physical processes, and offers the ability to isolate specific phenomena for study.
- Examine data from a large number of locations. Physical testing limits the number of locations that can be examined in the system. CFD permits the examination of a large number of locations in the area of interest, and yields a comprehensive set of flow parameters for examination.

## APPLICATIONS OF CFD

Computational Fluid Dynamics can be applied to different industries for different analytical capabilities. Some of the prime industries where CFD simulation is frequently used are:

- Aeronautics
- Automotive
- Building HVAC
- Chemical
- Power Generation
- Manufacturing
- Process Engineering
- Product Design + Optimisation
- Oil + Gas Industry
- Turbo Machinery, etc.

## LIMITATIONS OF CFD

- PHYSICAL MODELS
- NUMERICAL ERRORS
- BOUNDARY CONDITIONS

– CFD relies upon physical models of real world processes.

– CFD solutions could only be as accurate as the physical models.

– Solving equations on a machine also introduces numerical errors, e.g.

– Round-off error (owing to finite word size available on the computer, round-off errors will always exist).

– Truncation error (owing to approximations in the numerical models).

– Similar to physical models, the accuracy of the CFD solution is only as good as the initial boundary conditions provided to the numerical model.

SOURCES:

- (Jun. 2017). “Computational Fluid Dynamics And Applications.” Retrieved from http://crbtech.in/CAD-CAM-Training/computational-fluid-dynamics-applications/
- Patel, M. (Jan. 2013). “Computational Fluid Dynamics (CFD) Simulation Benefits Practical Applications.” Retrieved from http://www.hitechcfd.com/cfd-knowledgebase/cfd-simulation-benefits-practical-applications.html