Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 31 for “"Phase Averaged"”.
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LDV measurements in a Navy CPS fan
… the stator. Data were collected two ways: (1) averaged over the entire rotor cycle and (2) averaged at each rotation angle. Upstream bimodal probability densities of the axial velocity component were found in the cycle-averaged data. Bimodal distributions indicate instabilities in the …
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Velocity moment analysis on oscillatory flow above self-formed vortex ripples
… the data collected by Admiraal et al. (2006), phase-averaged and time-averaged mean velocities, root-mean-square speeds, turbulent kinetic energy, Reynolds shear stress, and higher order velocity moments including skewness factors, flatness factors, and turbulent diffusion factors were studied …
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Unsteady Turbulence Interaction in a Tip Leakage Flow Downstream of a Simulated Axial Compressor Rotor
… vortical disturbance, is also presented using phase and time averaged 3-component turbulence and pressure fluctuation measurements. These measurements are made for tip gap from 0.83% to 3.3% chord and streamwise locations from 0.772% to 1.117% blade spacing axially downstream of the cascade. …
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Visualization and velocity measurement of unsteady flow in a gas generator using cold-flow technique
… a strong component of the forcing frequency. Phase averaged mean velocities were observed to be well defined during charging and diminished during venting inside the cylinder. The jet flow penetrated most for the 4 Hz and least for the 12 Hz case. For the straight tube inlet comparison with a …
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An Investigation of the Irrotational Near Field of an Excited High Speed Jet.
… actuators (LAFPAs). The well-defined actuation phase allows for the phase averaging of the near-field pressure in order to separate the relevant features of the response from the background turbulence. The resulting phase-averaged signal illustrates a compact wave with a positive pressure …
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Direct simulation and deterministic prediction of large-scale nonlinear ocean wave-field
Despite its coarse approximation of physics, the phase-averaged wave spectrum model has been the only type of tool available for ocean wave prediction in the past 60 years. With the rapid advances in sensing technology, phase-resolved nonlinear wave modeling, and high performance computing …
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Airfoil-vortex interaction and the wake of an oscillating airfoil
… of the vortex generators trailing edge. Phase-averaged velocity measurements of the flow around the target airfoil were made with the airfoil at angles of attack of α = 0° and α = 10°. A close encounter with a counterclockwise rotating vortex was observed for both angles of attack, and a …
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Analysis of Multiple Degree-of-freedom Oscillatory Aquatic Propulsion
… fin ($A$), heave-to-pitch ratio ($h^*$), and phase offset between the two degrees-of-freedom ($\phi$) was used to explore a parameter space that encompasses and extends beyond the known biological domain. It was found that the shape of phase-averaged propulsive performance curves %($\etaQP$, …
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Design and Evaluation of an Active Yaw and Turbulence Generation System to Produce Unsteady Flow in Automotive Wind Tunnels
… anemometry measurements that were spatially averaged. Yaw performance under different operating conditions, such as flap oscillation frequency and amplitude, was evaluated in terms of the phase-averaged flow behavior, the shape of the yaw angle distribution, and spectral distribution of …
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EFFECTS OF WALL PLANE TOPOLOGY ON VORTEX-WALL INTERACTIONS IN A FORCED IMPINGING JET
… near-wall stresses. Multi-plane ensemble-averaged stereo PIV is employed to obtain volumetric, phase-averaged data that are subjected to a triple decomposition to quantify the unsteady behavior resulting from the coherent and stochastic fluctuations of the impinging structures. The effects …
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Blade tonal noise reduction using tail articulation at high Reynolds number
… the effects of tail articulation. Time averaged measurements of the stator wake by LDV show that Strouhal number of the tail articulation has a dominant effect on the time mean stator drag. Instantaneous phase averaged measurements of the stator wake by PIV show three regimes of the …
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A Method for Measuring Spatially Varying Equivalence Ratios with Application to Thermoacoustics
… emissions to be used for spatially resolved phase averaged equivalence ratio measurements. This is important as variations in local equivalence ratios can have a profound effect on flame behavior including but not limited to thermoacoustic instability, NOx and CO formation, and flame …
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Experimental investigation of turbulent flow in the near wake of a propeller
… to find mean and turbulence intensity magnitudes averaged behind the propeller disk. These measurements were made at 21 radial locations and 5 downstream locations: X/D=0.025, X/D=0.200, X/D=0.300, X/D=0.400, X/D=0.500. Finally, the wake from an individual blade was studied by sampling the …
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Near Wall Investigation of Three Dimensional Turbulent Boundary Layers
… with half-delta wing vortex generators attached. Phase-averaged data reveal asymmetrical vortex structures just downstream of the vortex generators. This is the first time any near wall data has been taken on any of these flows.
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Modeling wind forcing in phase resolving simulation of nonlinear wind waves
… which restricts the ability of traditional phase averaged models to simulate their complex dynamics. We develop a novel phase resolving model for direct simulation of nonlinear broadband wind waves based on the High Order Spectral (HOS) method (Dommermuth and Yue 1987). The original HOS …
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Size-selective sediment transport and cross-shore profile evolution in the nearshore zone
… zones along the cross-shore profiles. Existing phase-averaged wave and circulation models were utilized together with several new intra-wave modules for predicting important hydrodynamic parameters that were validated using the experimental data. A novel, multi-size sediment transport model was …
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A computer simulation model for predicting pesticide losses from agricultural lands
… of pesticides in the dissolved and adsorbed phases. Hydrologic data are generated by the comprehensive watershed model, FESHM; which contains an extended sediment detachment and transport algorithm. PLIERS uses first order rate equations to describe degradation and volatilization, and …
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An Experimental Investigation of Spanwise Vortices Interacting with Solid and Free Surfaces
… of a disturbing flap that generates vortices. Phase-averaged vorticity and turbulence level contours are estimated and presented. It is found that vortices with diameter the order of the boundary layer quickly diffuse and disappear while their turbulent kinetic energy spreads uniformly across …
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Turbulence Modeling and Simulation of Unsteady Transitional Boundary Layers and Wakes with Application to Wind Turbine Aerodynamics
… zero mean. Further processing the data through phase-averaging technique found phase lags along the chordwise locations and both the phase-averaged and mean profiles collapsed into the Law of Wall in the range of 0 < y+ < 50. The features of high blade loading fluctuations due to unsteadiness …
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A Novel Multiblock Immersed Boundary Method Enabling High Order Large Eddy Simulation Of Pathological And Medical Device Hemodynamics
… geometry after an endovascular repair (EVAR). Phase averaged velocity profiles, turbulence kinetic energy levels, viscous wall shear stresses and turbulence energy spectra are used to compare the similarities and differences between the blood flow patterns obtained. Presence of well developed …
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