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Development Of An Experimental Test Section For Forcing Unsteady Flow In A Linear Compressor Cascade Using Circular Rods, Patrick C. Wade
Development Of An Experimental Test Section For Forcing Unsteady Flow In A Linear Compressor Cascade Using Circular Rods, Patrick C. Wade
Theses and Dissertations
Upstream propagating waves impinging on a cascade of compressor blades were examined in an effort to better understand the influence of downstream components on high cycle fatigue in turbine engines. An array of cylinders was used to simulate the unsteady field generated by a rotor downstream of a set of stators. The unsteady flow upstream of a single cylinder and an array of cylinders, with and without an upstream cascade, was examined experimentally and computationally. Computational results indicate that the cylinders would only shed coherently when placed downstream of a set of blades. Coherent shedding is created when each of …
Computational Fluid Dynamics Investigation Of Vortex Breakdown For A Delta Wing At High Angle Of Attack, Jacob A. Freeman
Computational Fluid Dynamics Investigation Of Vortex Breakdown For A Delta Wing At High Angle Of Attack, Jacob A. Freeman
Theses and Dissertations
Using the commercially available FLUENT 3-D flow field solver, this research effort investigated vortex breakdown over a delta wing at high angle of attack (α) in preparation for investigation of active control of vortex breakdown using steady, along- core blowing. A flat delta-shaped half-wing with sharp leading edge and sweep angle of 60° was modeled at α=18° in a wind tunnel at Mach 0.04 and Reynolds number of 3.4 x 105. A hybrid (combination of structured and unstructured) numerical mesh was generated to accommodate blowing ports on the wing surface. Results for cases without and with along-core blowing …
Nonlinear, Transonic Flutter Prediction For F-16 Stores Configuration Clearance, Raymond G. Toth
Nonlinear, Transonic Flutter Prediction For F-16 Stores Configuration Clearance, Raymond G. Toth
Theses and Dissertations
Wing flutter, or more accurately limit cycle oscillation (LCO), has been an issue for the F-16 since its operational deployment. Different store configurations and the permutations of those configurations after weapons are released will cause LCO to either disappear or appear. Unfortunately, the current method used by engineers for predicting LCO onset is based on linear, subsonic aerodynamic theory with no corrections for transonic effects. Predictions using this method are often good in frequency, but can be far off in predicting onset speed, forcing flutter engineers to rely more on experience and interpolation from similar configurations to design flight test …