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Cfd Investigation Of Effect Of Depth To Diameter Ratio On Dimple Flow // Computational Fluid Dynamics Investigation Of Effect Of Depth To Diameter Ratio On Dimple Flow Dynamics, Robert B. Etter
Theses and Dissertations
This study aimed to further the understanding of laminar flow through a dimple with the goal of mitigating flow separation. Dimples of various depth to diameter ratios (0.05, 0.15) were examined for three different dimple diameters and chordwise locations, corresponding to diameter based (ReD) and chordwise location based (Rex) Reynolds number combinations of ReD 20500\Rex 5000, ReD 20500 Rex 77000, and ReD 9000 Rex 21000. For the last combination, a dimple of depth to diameter ratio of 0.25 was also examined. The dimples were placed in a flat plate located in a diverging channel causing an adverse pressure gradient encouraging …
Cfd Investigation Of Flow Past Idealized Engine Nacelle Clutter /// Computational Fluid Dynamics Investigation Of Flow Past Idealized Engine Nacelle Clutter, Matthew S. Caspers
Cfd Investigation Of Flow Past Idealized Engine Nacelle Clutter /// Computational Fluid Dynamics Investigation Of Flow Past Idealized Engine Nacelle Clutter, Matthew S. Caspers
Theses and Dissertations
This research modeled low-speed flow past idealized engine nacelle clutter in support of aircraft re suppression research. The idealized clutter was comprised of three vertical rows of staggered circular cylinders approximating typical nacelle obstructions such as fuel lines and wire bundles. Single-phase, Detached-Eddy Simulations (DES) were conducted using the commercial CFD solver, Fluent™, to resolve the flow-field dynamics inside the clutter element and determine mechanisms accounting for the failure of suppressant spray droplets from traversing the array under low-speed, free-stream conditions (ReD = 1, 575). The numerical models provided no evidence that span-wise vorticity or non-uniform shedding was responsible for …
Reduced Order Modeling For High Speed Flows With Moving Shocks, David J. Lucia
Reduced Order Modeling For High Speed Flows With Moving Shocks, David J. Lucia
Theses and Dissertations
The use of Proper Orthogonal Decomposition (POD) for reduced order modeling (ROM) of fluid problems is extended to high-speed compressible fluid flows. The challenge in using POD for high-speed flows is presented by the presence of moving discontinuities in the flow field. To overcome these difficulties, a domain decomposition approach is developed that isolates the region containing the moving shock wave for special treatment. The domain decomposition implementation produces internal boundaries between the various domain sections. The domains are linked using optimization-based solvers which employ constraints to ensure smoothness in overlapping portions of the internal boundary. This approach is applied …
Computational Investigation Of An Improved Cowl Concept For Hypersonic Propulsive Nozzles, Mark C. Butler
Computational Investigation Of An Improved Cowl Concept For Hypersonic Propulsive Nozzles, Mark C. Butler
Theses and Dissertations
The effects of placing a gas generator into the cowl of a hypersonic nozzle/afterbody were investigated computationally. Gas generator mass flow and deflection angle effects were analyzed for two nozzle/cowl geometries; an experimentally validated nozzle/cowl configuration evaluated at off-design conditions and a generic hypersonic propulsive nozzle evaluated at more realistic on design conditions. A combination of Van Leer flux-vector splitting and Roe flux-difference splitting finite volume computational algorithms were used to solve the unsteady two-dimensional Navier-Stokes equations based on planar, laminar flow, perfect gas equation of state assumptions. For the low speed off-design cases analyzed, gas generator effects on nozzle …