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.
Results
Showing 1 to 20 of 25 for “"Passive Flow"”.
-
The development of passive flow control vortices
Surface flow visualisation and Particle Image Velocimetry (PIV) were used to investigate the flow-field of sub-boundary layer vane vortex generators (VVGs) and steady jet vortex generators (SJVGs) in a separated flow at 20m/s. The vortex generators were mounted on a 2D bump which was situated on …
-
Exploring Passive Flow Control Techniques Applied to a Supersonic Multistream Rectangular Nozzle
<p>Passive control techniques are applied experimentally to examine different aspects of a supersonic multistream rectangular nozzle representing a modern airframe-integrated variable cycle engine. The flow is comprised of a core stream (M = 1.6) and bypass (M = 1.0) that merge behind a splitter …
-
Active and Passive Flow Control over the Flight Deck of Small Naval Vessels
… pilot workload. Because of the unsteady flow field and large mean velocity gradients, the envelope for flight operations is limited. This experimental investigation uses a 1:144 scale model of the U.S. Navy destroyer DDG-81 to explore the problem. Both active and passive flow control …
-
Investigation of Passive Flow Modulation for Full-Scale Air-Oil Coolers for Turbofan Engine Applications
… heat-exchanger with a trailing flap concept to passively modulate the amount of air flow that can flow through the heat-exchanger. The previous research has focused on fix flap positions and Computational models to support that experimental rig and test section. The current research builds upon …
-
Cooling enhancement of forced convection air cooled chip array through active and passive flow modulation
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1986.
-
Passive Flow Control with Shark Skin and the Relevance of Low Speed Streaks to Denticle Actuation
… as scales, which may be crucial to delaying flow separation. The teeth-like denticle morphology and flexibility of the scales measured by bristling angle vary along the shark's streamlined body [1]. Scales with narrow and long crowns have higher bristling angles at strategic locations, such …
-
Application of passive flow control to mitigate the thromboembolic potential of bileaflet mechanical heart valves: an in-vitro study
… needed. In this study, we explore the concept of passive flow controls that have been widely used in aerospace industry as a novel approach towards improving BMHV design. Passive flow control elements are small features on solid surfaces, such as vortex generators (VGs), that alter flow to achieve …
-
Molecular Dynamics Study of Solid-Liquid Heat Transfer and Passive Liquid Flow
… and nanoscale manufacturing, the maximum passive heat flux removal has been ~300 W/cm2 in pool boiling. Such limitations can be overcome by developing nanoscale thin-film evaporation based devices, which however require a better understanding of surface interactions and liquid vapor phase …
-
NATURAL AND VENTILATED CAVITATING FLOW OVER HIGH-SPEED UNDERWATER VEHICLE
… calculation of natural and ventilated cavitating flow. The mechanism of the free surface and bottom wall effects on the cavity profile and stability are studied. Then we present a new passive flow control method using small protrusions as cavitators. Compared with the case without the cavitator, …
-
The control of turbulent flows around bluff bodies by means of spanwise sinusoidal profiles
… structures. They are often exposed to turbulent flows, and the subsequent shedding of vortices gives rise to aerodynamic forces with large fluctuating components. As a result, significant oscillations are induced, which can lead to resonances and structural fatigue. To obviate these deleterious …
-
The aerodynamics of multi-element wings in ground effect
… field of aeronautics and offer insights into the flow physics of fundamental aerodynamic features. The experimental test rig consisted of a generic multi-element wing supported by an automated motion system. Measurements were obtained in the form of forces, surface pressures, oil flow …
-
Active Flow Control of Subsonic Flow in an Adverse Pressure Gradient Using Synthetic Jets and Passive Micro Flow Control Devices
… have shown the advantages of active and/or passive flow control devices for boundary layer flow modification. Many current and future proposed air vehicles have very short or offset diffusers in order to save vehicle weight and create more optimal vehicle/engine integration. Such short …
-
Effect of End-Plate Tabs on Drag Reduction of a 3D Bluff Body with a Blunt Base
… small tabs protruding perpendicularly into the flow. The body is tested in the Cal Poly 3ft x 4ft low speed wind tunnel. Testing is conducted in three phases.</p> <p>The first phase was the hot-wire measurement of streamwise velocity of the near wake behind the bluff body. An IFA300 thermal …
-
Numerical Investigations of a Pipe Jet With Coil Inserts With and Without Crossflow
… jets, aimed at advancing the understanding of passive flow control mechanisms and their effects on both free jet and jet in crossflow (JICF). It provides new insight into the fundamental physics of swirl-assisted mixing and offers a scalable framework for designing passive devices for jet …
-
Microchemical systems for kinetic studies of catalytic processes
… silicon reactor that incorporates a novel cross-flow design with a short pass multiple flow-channel geometry to reduce the gradients that often confound kinetics in macroscale reactors. The cross-flow geometry minimizes pressure drop though the particle bed and incorporates a passive flow …
-
The influence of hydrological variability on the spatial distribution and orientation of freshwater mussels (Bivalvia: Unionidae).
… southeastern Michigan was made using records of flow variability. The distribution and relative abundance of mussels (Bivalvia: Unionidae) was determined for three event (i.e., hydrologically flashy) and three stable (i.e., hydrologically stable) drainage basins. Multivariate analyses revealed …
-
Nonlinear Estimation and Control Methods for Mechanical and Aerospace Systems under Actuator Uncertainty
<p>Air flow velocity field control is of crucial importance in aerospace applications to prevent the potentially destabilizing effects of phenomena such as cavity ow oscillations, flow separation, flow-induced limit cycle oscillations (LCO) (flutter), vorticity, and acoustic instabilities. Flow …
-
Seasonal and interannual variability in the hydrology and geochemistry of an outlet glacier of the Greenland Ice Sheet
… average, and therefore, 222Rn can be used as a passive flow tracer of distributed system drainage. Supraglacial meltwater runoff estimated using two independent models was compared with ice velocity measurements across the glacier’s catchment. Major spikes of Jdis occurred after rapid …
-
Seasonal and interannual variability in the hydrology and geochemistry of an outlet glacier of the Greenland Ice Sheet
… average, and therefore, 222Rn can be used as a passive flow tracer of distributed system drainage. Supraglacial meltwater runoff estimated using two independent models was compared with ice velocity measurements across the glacier's catchment. Major spikes of Jdis, occurred after rapid …
-
Passive Turbulent Boundary Layer Control through 3D-Printed Dolphin Skin
… 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 adverse pressure gradient. The …
Page 1 of 2