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Showing 1 to 20 of 167 for “"flow separation"”.
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Flow separation control with rotating cylinders
… forward motion due to large areas of separated flow. These large forces severely limit maneuverability and reduce efficiency. Applying active flow separation control to ocean vehicles would reduce resistance during maneuvers and thereby improve maneuvering performance. In this thesis I discuss …
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Continuous flow separation techniques for microchemical synthesis
… to the development of continuous microfluidic separation tools. Safety, high heat and mass transfer rates, and cost savings all continue to motivate microreactor development as a research tool, but many reactions generate a variety of (by)products including solid particles, immiscible fluids …
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Analysis of two- and three-dimensional flow separation
… (1904) showed that streamlines in a steady flow past a two-dimensional streamlined body separate from the boundary where the skin friction (or wall shear) vanishes and admits a negative gradient. Although commonly thought otherwise, these separation conditions are purely kinematic: They can …
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Nonlinear dynamics of three dimensional fluid flow separation
Flow separation (the detachment of fluid from a no-slip boundary) is a major cause of performance loss in engineering devices, including diffusers, airfoils and jet engines. The systematic study of flow separation dates back to the seminal work of Prandtl in 1904. He showed that a two-dimensional …
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Flow Separation Control Using Synthetic Jets on a Flat Plate
… is to assess the effect of synthetic jets on flow separation. CFD simulation is conducted for laminar flow over a flat plate using the commercial software ANSYS FLUENT. The oscillating zero mass jet flow is simulated by imposing a harmonically varying boundary condition on the wall …
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Scour in regions of flow separation with free-surface effects
<p>Downstream of essentially all overflow and drop structures two distinct flow regimes are possible, one associated with a plunging flow, the other dominated by a flow that rides along the surface. Predicting the flow regime is important because diving-jet scouring rates are substantially faster …
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En-route airspace capacity under flow separation and scheduling constraints
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2002.
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Numerical Study on Flow Separation and Performance Characteristics of Slot Nozzle
… the nozzle. This slot allows atmospheric air to flow into the nozzle at low altitudes. While this is physically impossible to manufacture, CFD analysis can be conducted to understand how a passive air-breathing engine operates under different conditions. The slot nozzle is a precursor to …
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A simple criterion for three-dimensional flow separation in axial compressors
Most modem blade designs in axial-flow compressors diffuse the flow efficiently over 20% to 80% of blade span and it is the endwall regions that set the limits in compressor performance. This thesis addresses the estimation, control and mitigation of three-dimensional separation near the hub corner …
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A Computational Method for Flow Separation Detection and Control for Axial Compressor Airfoils
… stators stagger angle is increased 4 ° to induce separation on the modified GE stator type B and mass flow is injected to eliminate this separation on the suction surface of the airfoil. Using airfoil geometry obtained from NASA, 2 different CFD codes; NASA's SWIFT and Gambit-FLUENT are employed …
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Experimental studies of shear stress and flow separation in low Reynolds number flows
… investigation of the kinematic theory of separation in unsteady two-dimensional flows, and an evaluation of a novel optical shear stress sensor. Fixed separation in the rotor-oscillator flow is studied for steady, periodic, and quasi-periodic fluid motion. Experimental results are directly …
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Development of a Sensor for Inflight Detection of Three-Dimensional Flow Separation on a Wing
… need exists for a sensor capable of detecting flow-field separation on an airplane wing during routine flight operations. A sensor of this type could lead to both improved flight safety and increased performance. It would also contribute to future separation control technologies. A new idea is …
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A Study of Flow Separation in Overexpanded, Conical, Convergent-Divergentnozzles (With Special Consideration of the Effect of Wall Divergence on Mass Entrainment)
Made available in DSpace on 2014-12-05T19:15:59Z (GMT). No. of bitstreams: 1 6104334.pdf: 2870182 bytes, checksum: b780fb57b69e59818bf05e410f9423df (MD5) Previous issue date: 1961
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Skin Friction and Cross-flow Separation on an Ellipsoidal Body During Constant Yaw Turns and a Pitch-up Maneuver with Roll Oscillation
The skin friction and cross-flow separation location on a non-body-of-revolution (non-BOR) ellipsoidal model performing constant-yaw turns and a pitch-up maneuver, each with roll oscillation were studied for the first time. The detailed, low uncertainty, flow topology data provide an extensive …
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Inlet model testing facility preparation, injector calibration and preliminary testing of two two-dimensional inlet models at high incidence angles to study internal flow separation
An experimental study of internal flow separation at high incidence angles for two two-dimensional inlet models is presented. A description of the inlet testing facility includes the injector (which serves to drive the air through the inlet model), its control system, and the Virginia Tech 6-foot …
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An experimental study of unsteady separation in a two-dimensional flow
An experimental study of flow separation in an incompressible two-dimensional unsteady flow was undertaken with the aim of validating recently developed flow separation criteria, which are based on kinematic principles. Specifically, the so-called rotor-oscillator arrangement was utilized to …
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An Investigation of Dolphin-Groove Inspired Surface Patterning on Flow Control
A problem in many flow applications is boundary layer separation; this study investigates the passive separation control mechanism that could result from the micro-grooves found on dolphin skin (Tursiops truncates). A water tunnel was used to study a turbulent boundary layer over rigid 3D printed …
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Impacts of channel curvature on drag, mixing, and stratification in estuaries
… and channel curvature can lead to distinct flow processes in bends, e.g., secondary circulation and flow separation. An integrated approach combining field observations, idealized modeling, and realistic modeling is used to understand how curvature-induced flow processes affect hydrodynamic …
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Impacts of Channel Curvature on Drag, Mixing, and Stratification in Estuaries
… and channel curvature can lead to distinct flow processes in bends, e.g., secondary circulation and flow separation. An integrated approach combining field observations, idealized modeling, and realistic modeling is used to understand how curvature-induced flow processes affect hydrodynamic …
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Tidal dynamics and dispersion around coastal headlands
… shallow water equations forced by oscillatory flow are solved numerically for Gaussian headlands. The tidal flows around these headlands are shown to be characterized by flow separation and. transient eddy formation. Idealized models of flow separation and the transport and damping of vorticity …
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