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 24 for “"Boundary layer control"”.
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Submarine design optimization using boundary layer control
Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1997, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1997.
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Passive Turbulent Boundary Layer Control through 3D-Printed Dolphin Skin
… dolphin (Tursiops truncates) skin to mitigate boundary layer separation as a form of passive flow control, energizing the flow near the wall. A water tunnel generates a tripped turbulent boundary layer across a vertical test plate, and a rotating cylinder induces flow separation by creating an …
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Direct numerical simulation of microjets for turbulent boundary layer control
… an array of MEMS slot jets in a turbulent boundary layer for the purposes of flow control. Initial studies were used to first ascertain the correctness of the model and give insight into the performance characteristics of the devices. To this end, a flow and geometric parameter study was …
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Boundary Layer Control and Wall-Pressure Fluctuations in a Serpentine Inlet
In this thesis, the benefits of boundary layer control (BLC) in improving aerodynamic performance and engine stability were examined in a compact, serpentine inlet exhibiting flow separation. A 1/14-scale turbofan engine simulator provided the flow through the inlet. The inlet's mass flow was …
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Design of a high pressure ratio transonic compressor stage with active boundary layer control
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1996.
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Chebyshev spectral method for incompressible viscous flow with boundary layer control via suction or blowing
… with empirical closure relations to solve the boundary layer flow problem with or without suction, but lacks the option of flow control via blowing. The integral method is parameterized with the shape parameter H _ 6*/0 which cannot be applied to the blowing problem since 0 - 0 downstream of …
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Boundary-layer control of bluff bodies with application to drag reduction of tractor-trailer truck configurations
… of two fundamentally different concepts of boundary-layer control for the drag reduction of bluff bodies is studied experimentally. The methods are: (i) Moving Surface Boundary-layer Control (MSBC) involving momentum injection through one or more rotating elements (light hollow cylinders); …
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Drag reduction of cube-van through boundary-layer control: wind tunnel experiments and prototype road tests
… on energy conservation as well as pollution control, there has been considerable interest in improving propulsive efficiency of road vehicles. Reduction in aerodynamic resistance is one aspect of it. Although aerodynamically contoured automobiles has become a standard design practice. Trucks …
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Design and Numerical Evaluation of a Counter- Rotating Compressor in the Absence of Boundary Layer Control: Part II
… revitalized in research focused on the use of boundary layer control, again adding complexity and making the technology less than attractive to manufacturers. This thesis focuses on the design of a three-stage counter-rotating compressor without the benefit of boundary layer control. …
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Design and Numerical Evaluation of a Counter- Rotating Compressor in the Absence of Boundary Layer Control: Part I
<p>The purpose of this thesis was to design and evaluate a three stage counter-rotating compressor that employed well established design principles and technologies using a phased approach. The objective of the first phase was to generate the preliminary annulus shape and estimate the major …
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Hybrid Airfoil Design Methods for Full-Scale Ice Accretion Simulation
… of the study, therefore, reveals circulation control as the main design variable. To best utilize this fact, this thesis describes two innovative airfoil design methods for the design of hybrid airfoils. Of the two design methods, one uses a conventional flap system while the other only …
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Dynamic characterization and active control of unstarts in a near-isentropic supersonic inlet
… of the inlet and by an efficient boundary layer control mechanism. Thus the resulting inlet design has reduced stability to unstart in the face of atmospheric and engine-born disturbances, necessitating active control. An active stabilization bleed system is introduced that …
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Improving the performance of aerofoil sections using momentum transfer via a secondary flow
Aerodynamic flow control can improve aerofoil performance by influencing the natural growth of boundary layers, which develop on the surface of vehicles moving in viscous fluids. Many active and passive techniques have been developed to reduce drag and/or increase the lift of aerofoil …
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Parametric Study of Aerodynamic Performance of an Airfoil with Active Circulation Control Using Leading Edge Embedded Cross-Flow Fan
… near the leading edge of an airfoil to actively control the boundary layer for lift and thrust enhancement has been proposed. The design places a cross-flow fan near the leading edge of an airfoil and flow is drawn in from the pressure side of the airfoil, energized and expelled out to the …
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Transition from laminar to turbulent flow around an airfoil
… turbulent kinetic energy. To include laminar sublayer into the computational domain, a multi-layer grid and a cubic-slpine grid were introduced through a conservative form of coordinate transformation. The flow structure varies with the Reynolds numbers. For an airfoil at low Reynolds numbers …
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Optimization of an airfoil's performance through moving boundary control
The boundary-layer behavior over an airplane's wings is of great importance in take-off and landing of the airplane. If its angle of attack is increased past a critical value, the flow separates from the lifting surface, resulting in a drastic loss of lift and a major increase in drag. In response …
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Control of the abyssal ocean overturning circulation by mixing-driven bottom boundary layers
… results in vigorous upwelling in the bottom boundary layer (BBL) along the sloping seafloor and downwelling in the stratified mixing layer (SML) above; their residual is the overturning circulation. This boundary-controlled circulation fundamentally alters abyssal tracer distributions, with …
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Control of the abyssal ocean overturning circulation by mixing-driven bottom boundary layers
… results in vigorous upwelling in the bottom boundary layer (BBL) along the sloping seafloor and downwelling in the stratified mixing layer (SML) above; their residual is the overturning circulation. This boundary-controlled circulation fundamentally alters abyssal tracer distributions, with …
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Air jet vortex generators for wind turbines
Air jet vortex generators are a boundary layer control device and as such can effect a significant delay to the stall of an aerofoil. They can also reattach a separated flow, as long as the angle of attack is less than the air jets 'on' stall angle. A wind tunnel model was built and tested and then …
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Creep characterization of single crystal silicon in support of the MIT Micro-Engine Project
… propulsion for small unmanned air vehicles, boundary layer control, a micro-turbine expander for miniature cooling system: a turbo pump for micro-rocket engines, and a micro-motor driven pump or compressor for fluid handling applications. To characterize the creep behavior, representative …
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