High Speed Volumetric Velocity Measurements

Submitted to: Sea-Based Aviation (code 351), David Gonzalez PI: Dr. Stephen Lynch; co-PI: Dr. David WilliamsMechanical Engineering,Pennsylvania State University This proposal describes laser systems that can be used to measure time-varying volumetric velocityfields in a wide range of flow conditions relevant to Department of Defense (DoD) applications. These types of measurements are critical to understand the fundamental physics of complex flows and the effectiveness of control/manipulation techniques that can give unparalleled advantage to DoD weapon systems. As one example, an unsteady streamwise vortex can develop in the inlet of an embedded engine, which impacts the engine efficiency and limits the aggressiveness of aircraft maneuvers. Another example is tip leakage flows in turbomachinery which are a major contributor to efficiency loss in aircraft engines. Three-dimensional time varying velocityfields are challenging to acquire but are ubiquitous in fluid dynamics applications. Recent developments in laser-based measurementtechniques have resulted in two top candidates for time resolved 3D volumetric velocities: particle image velocimetry (PIV) and particle tracking velocimetry (PTV). The proposed equipment here would triple the energy available relative to the PI#s existing high repetition rate laser to make volumetric velocity measurements possible. This would be applied to a currently funded Office of Naval Research project investigating vortex breakdown in highly turbulent flow, as well as an Air Force Research Lab funded work investigating the impact of heat transfer augmenting surface features at the entrance of an engine inlet duct and Department of Energy fundedwork investigating the ability to measure total pressure fields in non-adiabatic compressible flow. In addition, the proposed system would significantly augment both graduate and undergraduate education and training opportunities at Penn State. The proposal team has wide experience in training graduate students to use advanced laser-based diagnostics on DoD funded projects, and have established robust undergraduate research experiences in their labs. The proposed equipment is also planned for use in an NSF-AFOSR co-fundedundergraduate research program at Penn State in the area of propulsion and power generation.This Abstract is Publically Releasable