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Showing 1 to 16 of 16 for “"passive flow control"”.
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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 …
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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 …
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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 …
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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 …
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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 …
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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, …
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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 …
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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 …
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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 …
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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 …
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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 …
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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 …
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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 …
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Unsteady separation control on wind turbine blades
… wind turbine operating environments, such as inflow turbulence, wind gusts and sustained yaw misalignment. The unsteady separation due to dynamic stall can lead to excessive loads, much larger than the design loads for the turbine, and vibrations in the blade, leading to fatigue damage. …
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Control of supersonic axisymmetric base flows using passive splitter plates and pulsed plasma actuators
… investigation evaluating the effects of flow control on the near-wake downstream of a blunt-based axisymmetric body in supersonic flow has been conducted. To better understand and control the physical phenomena that govern these massively separated high-speed flows, this research examined …
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The effects of micro-vortex generators on normal shock wave/boundary layer interactions
… interactions (SWBLIs) are complex flow phenomena that are important in the design and performance of internal supersonic and transonic flow fields such as engine inlets. This investigation was undertaken to study the effects of passive flow control devices on normal shock …