A Monte Carlo Study Examining the Potential of Experimental Design Strategies for Wind Tunnel Testing

Raymond Hill, Derek Leggio
2010 U.S. Air Force T&E Days 2010   unpublished
Wind tunnel test campaigns involve a large number of experimental data points, can take a long time to accomplish, and can consume tremendous resources. Design of Experiments (DOE) is a systematic approach to experimental design and analysis that has the potential to improve the efficiency and effectiveness of wind tunnel testing. We employ a legacy wind tunnel test campaign and compare the resulting data from that campaign to data generated using smaller experimental design strategies. The
more » ... arison is accomplished using a Monte Carlo sampling methodology coupled with a statistical comparison of the estimated surfaces. Initial results suggest a tremendous opportunity to reduce wind tunnel test efforts without losing test information. I. Introduction Wind tunnel testing is important for the Developmental Test and Evaluation (DT&E) of United States Air Force (USAF) aeronautical systems including aircraft, spacecraft, and munitions. Most air-based systems are tested in a wind tunnel's controlled laboratory environment to assess overall aerodynamic performance. Wind tunnel engineers also test design concepts, optimize configurations, or study stability and control (S&C) characteristics of new and modified aerospace systems and may get involved in validating a modeling and simulation effort or conducting systems analysis prior to open-air flight test. Wind tunnel output is used to support performance evaluation, trade-off studies, risk analysis, assessments of potential operational utility, and to demonstrate that the development process is complete and that the system meets specifications. The overall effectiveness of wind tunnel test programs can be improved. The significant time and resources required in wind tunnel testing directly impacts the overall system development cycle length and overall system cost. For instance, current high-performance military aircraft development programs require up to 3,700 wind tunnel test hours in the conceptual design phase and up to 18,500 hours in the development/validation phase. 1 The Arnold Engineering and Development Center (AEDC), a world-class flight simulation test facility, has sought "reductions of up to 75 percent in costs and cycle time in developing and fielding new weapons systems". 9 Our study supported AEDC. Conventional wind tunnel tests are often based on the one-factor-at-a-time (OFAT) testing approach. An OFAT approach involves varying one factor across its range while holding all other factors constant. However, OFAT methods are not particularly effective in terms of cost, effort, or in controlling experimental uncertainty, detecting variable interactions, or producing minimum variance predictions. 7 We examine how designed experiments, as an alternative to OFAT approaches, can potentially reduce overall wind tunnel test efforts and examine any information loss due to such reductions. We use a Monte Carlo experiment that systematically compares the information obtained from a traditional wind tunnel campaign with information that would be obtained via more advanced experimental design strategies.
doi:10.2514/6.2010-1715 fatcat:7eprwpswezbbhb27gkhfesklqa