1. AATC/FDTC Discussion Group Benchmark Experiments for Computations of Airframe Noise Meelan Choudhari and Miguel Visbal Aerospace Sciences Meeting, Reno, NV 01-07-2008

2. 2 Overall Goal Promote development of benchmark experiments + pertinent computations by multiple teams (a priori/concurrent/a posteriori)  Canonical, non-proprietary  Chain-of-causality vs. cause and effect 

3. 3 Today’s goal Define strategy to achieve this goal  Near term –available/almost available datasets  Longer term –on the horizon datasets that can be improved to benchmark quality with collective input Brief Presentations  Lessons learned from previous CAA workshops (Chris Tam)  Experimental benchmarks: CAA needs(Jan Delfs)  Complex configurations: industrial perspective (high-lift configurations, undercarriage, propulsion-airframe integration,…): Philippe Spalart  Simpler configurations: available/anticipated datasets –Tandem cylinders –Trailing edge –Rod airfoil interaction  Complex configurations: industrial perspective (high-lift configurations, undercarriage, …) Open floor discussion: strategy & initial steps  Consensus near term configurations  Plan for complex configurations

4. 4 AIAA discussion groups are purely technical, i.e., every one participates with their own nickel! AIAA Technical Discussion Groups engage in either preliminary or longer term exploration and discussion of a broad set of technical issues and technical needs, producing, at their discretion, reports and recommendations of interest to the broader technical community. The exchange is limited to technical information and no monetary sponsorship of research efforts is involved.

5. 5 AFN Benchmark: Necessary Criteria (Adapted from: Settles and Dodson 1993, Transition Study Group 1975) –Baseline Applicability »Scope relevant to airframe noise, adequate depth + breadth of flow AND acoustic measurements –Specific Applicability »Provide useful metric for key fluid dynamics/aeroacoustic phenomenon – Canonical, non-proprietary –Well defined experimental configuration » Geometry, facility, flow & model surface quality –Adequate resolution (space and time) –Well defined experimental error bounds » Accuracy, repeatability, facility dependence –Adequate documentation –Consistency/robustness of findings »Consistent behavior across neighboring Re/Mach No.; no surprise resonances » Facility dependence

6. 6 Near Term Datasets: Promising Candidates –Rod cylinder interaction (Jacob et al.) –Pair of cylinders in tandem (NASA Langley) –Trailing edge noise: cambered and/or swept airfoil –Others? »Wing tip (JAXA) –

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