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Showing 1 to 20 of 71 for “"Adverse pressure"”.
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Similarity in adverse pressure gradient turbulent flows
… is to experimentally generate increasingly adverse pressure gradient flow data for comparison with published data, to find similarities allowing categorization leading to improved flow prediction.
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Vortical flows in an adverse pressure gradient
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1993.
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Pressure signature in adverse-pressure-gradient wall bounded turbulent flows
… of universal patterns in wall-bounded adverse pressure gradient turbulent flows. For this purpose, the experimental work has been carried out towards further understanding of this class of flows, especially when the pressure gradient is increasingly adverse. Adverse pressure gradient …
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Numerical Simulation of Vortex Generating Jets in Zero and Adverse Pressure Gradients
… blowing of angled jets, subjected to a zero pressure gradient, yielded excellent agreement with the PIV data in terms of vortex formation and strength. Observed flow features include primary and secondary vortices, where the primary vortex eventually dominates the downstream region. A shell …
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Active Flow Control of Subsonic Flow in an Adverse Pressure Gradient Using Synthetic Jets and Passive Micro Flow Control Devices
… result in boundary layer separation and loss of pressure recovery which reduces engine performance and in some cases may cause engine stall. Deployment of flow control devices can alleviate this problem to a large extent; however, almost all active flow control devices have some energy penalty …
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A turbulence model for steady and unsteady boundary layers in strong pressure gradients
… steady and unsteady boundary layers in strong adverse pressure gradients is described. The model is developed in a rational way based on an understanding of the flow physics obtained from recent experimental observations. The turbulent shear stress is given by a mixing length model, but the …
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Boundary layer transition in simulated turbine blade flow
… regions was observed to remain intact for severe adverse pressure gradients, including cases where separation bubbles were present during the early stages of transition.<br/><br/>An original correlation for the spot formation rate parameter, N, was developed using the adverse pressure gradient …
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Prediction of transitional boundary layer properties for CFD software in engineering flows
… a variety of flows including zero and constant adverse and favourable pressure gradients, and also the varying pressure gradient Rolls Royce T3C flows. The method gives good prediction of skin friction and transition length when the start of transition was in zero and favourable pressure …
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Mitigating Engine Unstart in Scramjets with Porous Bleeders
… of porous bleeder design parameters such as pressure jump coefficient and bleeder size on isolator effectiveness and unstart prevention was evaluated. Results indicated that porous bleeders delayed flow separation and reduced adverse pressure gradients, thereby enhancing isolator performance. …
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Study of Far Wake of a Surface-Mounted Obstacle Subjected to Turbulent Boundary Layer Flows
… Reynolds number of the flow and manipulating the pressure gradient distributions using a NACA 0012 airfoil placed within the wind tunnel test section. The measurements were acquired utilizing a spanwise traversing boundary layer rake and a point pressure sensing microphone array. The findings …
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Effects of Supercooled Large -Droplet Icing on Airfoil Aerodynamics
… chord, and the separation bubble formed over the adverse pressure gradient of the clean airfoil, which started at 75% chord. The effect of the ice shape on the NLF 0414 was not as severe as on the NACA 23012m because the lift was much more aft loaded.
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Evaluation of Turbulence Models for Unsteady Separation
… in many physical flows due to time-varying adverse pressure gradients. This phenomenon may result in increased drag, decreased lift, and loss of efficiency or failure in flow devices. It is, therefore, important to predict and analyze unsteady separation in the design of flow devices. …
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Experimental and numerical studies of flows over forward facing steps in pressure gradients
… and numerical studies of the effects of adverse pressure gradients (APG) and Reynolds numbers on flows over forward facing steps (FFS). For the experimental work, particle image velocimetry was used to conduct velocity measurements at several locations downstream of the FFS. Proper …
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Design and analysis of an active underbody aerodynamic device for tractor trailers
… recirculation region and reduced the negative adverse pressure in the wake. A novel mechanism is also developed to allow for the active deployment of the device to mitigate some operational issues such as roadway protrusions, parasitic drag at low speeds, snow and dirt accumulation.
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Camada limite de temperatura com gradiente de pressão adverso
… is modified to consider the presence of the pressure gradient. The compressible laminar boundary layer in an adverse pressure gradient is analyzed on the basis of the momentum and thermal integral equations. A method of calculating the boundary layer as function of the Mach number, uniform …
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A Computational Fluid Dynamics Study on the Aerodynamic Performance of Ram-Air Parachutes
… to predict flow separation and reattachment from adverse pressure gradients. The high complexity of the 3D model is handled using appropriate boundary conditions and cleaning geometric tools within the CFD software.</p>
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Supersonic flows of Bethe-Zel'dovich-Thompson fluids in cascade configurations
… dynamics, Γ, is negative over a finite range of pressures and temperatures. The equation of state is the well-known Martin-Hou equation, and the numerical scheme is the explicit predictor-corrector method of MacCormack. Numerical comparisons between BZT fluids and more classical fluids such as …
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A Numerical Study of Internal Flow Effects on Skin Friction Gages
… skin friction sensor in the presence of a pressure gradient has always been a concern. These effects are studied here with a three-dimensional, Navier-Stokes code based on a finite element method technique. Numerical solutions for cases in which one or more design parameters were varied are …
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Modelling of Wall Pressure Fluctuations Induced by Turbulent Boundary Layer Flow
… to predict the power spectral density of wall pressure fluctuations in the turbulent boundary layer. From the analysis of current semi-empirical models and a large survey of experimental data, it was found that the models proposed by Goody and Smol'yakov have the lowest mean squared error when …
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Viscous-inviscid interactions of dense gases
… of Bethe-Zel’dovich-Thompson (BZT) fluids at pressures and temperatures on the order of those of the thermodynamic critical point. A BZT fluid is a single-phase gas having specific heat so large that the fundamental derivative of gas dynamics, Γ, is negative over a finite range of pressures …
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