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Showing 1 to 20 of 20 for “"prolate spheroid"”.
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Unsteady flow over a 6:1 prolate spheroid
The flow over a 6:1 prolate spheroid undergoing transient maneuvers is studied. The Dynamic Plunge-Pitch-Roll (DyPPiR) model mount provides the unique capability to simulate truly unsteady maneuvers in a wind tunnel. The DyPPiR is presented along with several transducer systems used to study …
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Mean velocity and turbulence measurements of flow around a 6:1 prolate spheroid
… of the three-dimensional flow around a 6:1 prolate spheroid model 1.37 m long were conducted in the separation and near wake regions along the leeward side. Mean velocity flow field measurements, at α = 10∘ and 15∘ , and at Re = 1.3 x 10⁶ (U<sub>re</sub>= 15.2 mls) and 4.0x 10⁶ (Ure=45.7 …
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An experimental study of flow over a 6 to 1 prolate spheroid at incidence
… dependent issue, the flow over a 6 to 1 prolate spheroid, which is a generic three-dimensional body, is investigated. For the identification of the general flow pattern and better understanding of the flow field, surface-oil-flow visualization tests and force and moment tests were …
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Octant Analysis of the Reynolds Stresses in the Three Dimensional Turbulent Boundary Layer of a Prolate Spheroid
… leeside (x/L=0.76-0.78, φ=105°-130°) of a 6:1 prolate spheroid at 10° angle of attack. The Reynolds number for the flow was Re<sub>L</sub>=4.2x10⁺⁶. The LDV data of Chesnakas, Simpson, and Madden (1994) were the basis of examination. This data set employed a post-processing technique for …
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Non-Rayleigh scattering by a randomly oriented elongated scatterer
… of a randomly rough, randomly oriented prolate spheroid that is randomly located in a beampattern are investigated from physics-based principles both analytically and by Monte Carlo methods. This is a direct-path geometry in which reflections from neighboring boundaries are not a factor. …
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Non-Rayleigh scattering by a randomly oriented elongated scatterer
… of a randomly rough, randomly oriented prolate spheroid that is randomly located in a beampattern are investigated from physics-based principles both analytically and by Monte Carlo methods. This is a direct-path geometry in which reflections from neighboring boundaries are not a factor. …
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Separation and wakes over three-dimensional bodies
The laminar flow over a prolate spheroid was investigated via flow visualization and Laser-Doppler Velocimetry. Experiments were conducted in a water tunnel and the flow was visualized with dyes. The measurement of three-dimensional boundary layers required a special design of the laser optics. …
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Investigating the Effect of an Upstream Spheroid on Tandem Hydrofoils
… used to investigate the influence of an upstream prolate spheroid body on tandem pitching hydrofoils. The model is validated by performing separate CFD simulations on the body and pitching hydrofoils and comparing results to existing experimental data. The simulations were run for a range of …
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Refinement and Verification of the Virginia Tech Doppler Global Velocimeter (DGV)
… a calibration wheel and in the wake of a 6:1 prolate spheroid. These attempts were hampered by poor performance of the Nd:YAG laser and one of the digital cameras used in this research. While the magnitudes of the velocities acquired from the calibration wheel were noticeably higher than those …
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An Experimental Investigation of Pressure Fluctuations in Three-Dimensional Turbulent Boundary Layers
… the separating flow about the leeside of a 6:1 prolate spheroid at angle of attack. Measurements were made at two angles of attack, 10° and 20°, and two axial locations, x/L = 0.600 and x/L = 0.772, in this type of flow. Spectral scaling is discussed and various scaling combinations of the …
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Behavior of Polymer Solutions and Melts in Shearing and Elongational Flow Using Streak Photography and Birefringence
… constant free stream flow past a long slender prolate spheroid. Elongation rates in the vicinity of the cylinder axis are significantly enhanced over those in the mainstream and in a region within about two diameters downstream of the cylinder end the kinematics can be classifed as "strong" …
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Development and Testing of the Virginia Tech Doppler Global Velocimeter (DGV)
… in the separated wake region behind a 6:1 prolate spheroid. Detailed uncertainty analysis techniques demonstrated that, under the proper conditions, the system is capable of making velocity measurements with approximately +/- 2m/s uncertainty.
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Orientation dependence of the acoustic backscatter for elongated zooplankton
… Born approximation (DWBA) and the geometry of a prolate spheroid, an analytic formula for the backscatter cross section as a function of orientation angle is derived. A directivity pattern is determined from the analytic formula and the width of the main lobe (beam width) is computed. The …
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Optimal design of municipal and irrigation water distribution systems
… dependent issue, the flow over a 6 to 1 prolate spheroid, which is a generic three-dimensional body, is investigated. For the identification of the general flow pattern and better understanding of the flow field, surface-oil-flow visualization tests and force and moment tests were …
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An investigation into the application of LES and DES for prediction of flow and forces around an IACC yacht keel and marine bodies
… bodies: a NACA 0012 section trefoil, a 6:1 prolate spheroid at angles of incidence and an assymetric America's Cup yacht keel. Quantitative comparisons included predictions of values of global force coefficients around the geometrics, pressure and friction coefficients on the surface, and …
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A Data Driven Modeling Approach for Store Distributed Load and Trajectory Prediction
… distributed pressure loads of a pitching up prolate spheroid. Results indicated that POD was the most efficient approach for surrogate model generation. For the second sub-task, a POD-based surrogate model was derived from CFD simulations of an oscillating prolate spheroid subject to varying …
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Effects of plasma proteins on the sieving of macromolecular tracers in the kidney
… effect. Results were obtained also for oblate or prolate spheroidal solutes and for fibrous media with multiple fiber radii. For constant total fiber volume fraction, an increase in the amount of a second, smaller fiber decreased the partition coefficient of a spherical solute, whereas an increase …
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Aerodynamic and Aeroacoustic Analysis of Low Reynolds Number Propellers Using Higher-Order RANS Transition Turbulence Modeling
… flows, demonstrated using the case of a prolate spheroid. This underscores the capability of Reynolds stress models to accurately capture complex flow curvatures, improving upon the capabilities of linear eddy viscosity models. The transition model, integrated into OpenFOAM, was then …
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Methods in wave propagation and scattering
… a permeable, highly but not perfectly conducting prolate spheroid under axial excitation, expressed in terms of an infinite matrix equation. The spheroid is assumed to be embedded in a homogeneous non-conducting medium as appropriate for low-frequency, high-contrast scattering governed by …
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Development and Application of Low-Order Computational Models of the Left Ventricle
… The LV is represented as a thick-walled prolate spheroid containing helical muscle fibers with nonlinear passive and time-dependent active contractile properties. The displacement field during the cardiac cycle is described by three time-dependent parameters, using a family of …