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Reducing the Design Cycle

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CEI’s CFD Consulting Services

Automotive manufacturer uses CEI’s consulting to reduce the design cycle of a new car

 

Summary
A specialized car company needed to design both a production version of their new car, as well as a version of the same car for racing applications. In the past, in order to achieve both of these goals, the manufacturer typically had to design the production version of the car first, and then would back out a racing version. This method of car design results in a long lead time, and a delay in the use of the race car version to help promote the new car model.

 

To achieve a racing version of the car at the same time as the production version, the car manufacturer then needed to employ a very short design cycle program. This allowed them to develop the racing version of the car shape and layout without impacting the overall schedule of the production version. In order to achieve the very short design cycle for this type of approach, an improved method for designing, analyzing and understanding the car’s aerodynamic performance was needed. To achieve this design goal, computational fluid dynamics (CFD) simulations of the aerodynamic configurations were employed to analyze various design revisions. Ultimately, this reversal of the typical design cycle allows for a quicker design cycle, utilizing more detailed and accurate analysis of the proposed design prior to any manufacturing or testing.

 

Background

Kevin Colburn, of Computational Engineering International (CEI), utilized his CFD expertise for this short design cycle project for high performance aerodynamic analysis. With over 13 years of experience in the field of high end, large model CFD analysis, and 6 years of experience utilizing CFD tools and techniques to determine the aerodynamic performance of McLaren’s F1 car program, CEI’s consulting services were perfectly matched for this CFD project.

 

Project Timeline
The project started with the client’s delivery of an IGES file description of the external shape of the car, along with the key internal ducting and radiator layout configurations. After a few brief discussions with the manufacturer, Mr. Colburn began the process of assessing the car’s aerodynamic performance. A highly detailed grid for the car’s wings was developed with block structured grid aligned to the wing and its wake. Detailed grids for the external portions of the car, wake, and outer domain were then created. The model was assembled into the appropriate CFD solver , and the appropriate boundary conditions and monitoring aspects of the model were easily set up. A parallel CFD solver run was then performed to quickly turn around a high fidelity 14-million cell external aerodynamic CFD model in only 2 days.

 

Analysis
The model and results were then brought into CEI’s EnSight visualization package for analysis of the solution, generation of images and animations, and portrayal of this analysis and results back to the manufacturer’s team of aerodynamic engineers, design engineers and managers. CEI’s self-extracting EnLiten files provided the means to transfer the information to the customer. EnLiten is a geometry viewer used to display, manipulate and analyze complex visualization scenarios generated by EnSight. The EnLiten files allowed the customer to have the full 3D, rich geometric and analytical results without needing to purchase licenses, or utilize expert knowledge of CFD or EnSight. These files greatly enhanced the client’s knowledge and understanding, allowing the customer to be an integral part of the analysis and solution.

 

The complete CFD analysis, from original IGES surface, to delivery of the final solution to the customer took only 2 weeks, and was completed by a single individual. Traditionally, this type of design iteration done with typical experimental techniques (Wind tunnel testing) could take several months to perform, and may still not provide the understanding of the car’s operation. Usually, this type of large, highly detailed complex flow analysis using computational methods would take several months to complete in its entirety. This very short design and analysis iteration was made possible by a combination of powerful CFD tools and expert use/application of these tools.

 

 

Results
With Mr. Colburn’s expertise, this type of analysis and design iteration need only take a few weeks.  The short turnaround time of this type of analysis allowed the customer to easily implement any required alternations or adjustments to the design based on CFD analysis. The use of CFD, in this case, became a very powerful driving force in the design process, rather than being used for offline experiments or studies. The power of the CFD model and EnSight in providing insight into the performance of the device, explained the what, the how, and the why of the simulation, which could then be communicated to the analyst, as well as the designers and managers. This communication within an organization fundamentally impacted the design process.

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