PRATT & MILLER
CFD Flow Viz – Streamlines
CFD iso-Vortical Surfaces from above and below
and ongoing development is divided between CFD and tunnel testing based on relative efficiencies. Once a full-scale vehicle is complete, ontrack testing is performed and, if budgeted, full-scale wind-tunnel testing is performed. Again, correlation between methods is checked and ongoing development distributed among the various test plans. When the final production configuration is decided, a full battery of aero computations and testing is executed to build aero models for engineering support of the deployed vehicles. Pitch-heave, yaw, and roll mapping is completed and the test data is regressed into equations and/ or tables used in vehicle simulation. Mapping of adjustable aero settings is also performed. With the resulting comprehensive aero models integrated into vehicle simulation and analysis 2010 | WIND TUNNEL INTERNATIONAL
tools, race engineers have maximum ability to understand interactions and trade-offs between aerodynamics and other vehicle and chassis settings and to optimize the overall vehicle performance for any race track and environmental conditions. The results of this process have been demonstrated repeatedly when new PME vehicles meet and exceed performance targets the first time they hit the track and go on to compete successfully in their respective racing categories. Further, translating motorsportbased methodologies to non-motorsport development environments has proven successful for PME with aerodynamics being a prime example. Processes and tools developed for the competitive short-cycle-time motorsport arena can meet the challenges faced by OE automotive and defense programs.
AERO METhODS DETAiL: The various aero methods available for PME programs have different levels of utility depending on the scope and phase of the program and the topic being investigated. Depending on program content, timing, and budget, PME aero development is planned with a mix of methods to best achieve overall program objectives. Thoughtful integration and correlation of the different methods builds confidence in both absolute and relativetrend accuracy and in resulting development decisions. PME has extensive experience with correlation of surface pressures, forces/ moments, and ride height sensitivity between CFD, Wind Tunnel, and On-Track testing. Understanding the similarities and differences between methods is the first step in maximizing the outcome of a given aero program. 77