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Showing 1 to 20 of 36 for “"Recirculation Region"”.
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Flow Visualizations and Measurements of Turbulent Structures in Drag-Altered Axisymmetric Compressible Base Flows
… present in the recompression and reattachment regions of the flowfield are shown to de-stabilize the turbulent structure organization. The mean structure statistics of all drag-altered flowfields demonstrate that the dominant organization present upstream is significantly weakened or lost due …
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Measurements and Visualizations of a Three-Dimensional Compressible Base Flow
… fan, a separated shear layer, an asymmetric recirculation region, and a turbulent wake. A strong secondary circumferential flow, which develops along the afterbody due to pressure gradients on its surface, results in the entertainment of fluid into the base region from the leeward portion of …
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The characterization of the flowfield of a dump combustor
… effect was the difference between the inherent recirculation regions for each case. Combustion decreased the length of the region by approximately 50 percent, while increasing the maximum negative velocities. This made for a more compact, but stronger, recirculation region. Since the …
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Analysis of Ship Airwakes Using Modal Decomposition
… different crosswise planes over the flight deck region of the ship model, with and without the effect of a simulated atmospheric boundary layer (ABL).</p> <p>Spatiotemporal analyses of the TR-PIV measurements were performed using modal decomposition, and the modes were decomposed further based on …
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ΑΡΙΘΜΗΤΙΚΗ ΚΑΙ ΠΕΙΡΑΜΑΤΙΚΗ ΜΕΛΕΤΗ ΡΟΩΝ ΣΕ ΜΟΝΤΕΛΑ ΠΟΡΩΔΟΥΣ ΜΕΣΟΥ
… OF MACROSCOPIC (DARCY SCALE). TO DETERMINE THE RECIRCULATION REGION IN THE PROE GEOMETRY IS OF HIGH IMPORTANCE TO UNDERSTAND TRANSPORTATION PHENOMENA AND GENERALLY THE MECHANISM OF THE FLOW IN MICROSCOPIC LEVEL. TO STUDY THE ABOVE, THE THESIS USES EXCEPT THE NUMERICAL METHOD (FD), EXPERIMENTAL …
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Eddy forcing of the mean circulation in the western North Atlantic
… momentum, vorticity, and heat balances in three regions of the Western North Atlantic -- the northern recirculation, the southern recirculation, and the mid-ocean. The data from the last decade of field experiments suggest somewhat different conclusions from the earlier analysis of Harrison …
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Design and analysis of an active underbody aerodynamic device for tractor trailers
… for overcoming aerodynamic drag. The underbody region of a tractor-trailer is responsible for up to 30 % of the aerodynamic drag on tractor-trailers, which is the highest drag created by any region on the vehicle. In this study, a novel concept of an active underbody drag reduction device is …
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The effect of entrainment on jet impingement heat transfer
… jet arrays show that entrainment of air in the recirculation region between the jets can significantly affect the heat transfer rates. Comparison of the analytical model to the measured heat transfer rates for jet arrays shows that the single jet model can be successfully applied to jet arrays …
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Investigation of in-nozzle flow characteristics of fuel injectors of IC engines
… the injector hole when it interacts with the recirculation region at the entrance of the injector hole. Cavitation simulations inside a single-hole injector were next performed. Simulations were assessed by comparing predicted vapour volume fraction with measurements. Influences of liquid and …
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Control of supersonic axisymmetric base flows using passive splitter plates and pulsed plasma actuators
… consisted of inserting splitter plates into the recirculation region. The active control technique utilized energy deposition from multiple electric-arc plasma discharges placed around the base. The flow-control authority of both methodologies was evaluated with experimental diagnostics including …
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Active control of massively separated high-speed/base flows with electric arc plasma actuators
… a local thickening of the shear layer in the region of the disturbances caused by the actuator. A slight increase in thickness was also observed away from the disturbance. Disturbances were able to be tracked at all frequencies and translated along the shear layer at a convective velocity of …
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Iced Airfoil Separation Bubble Measurements by Particle Image Velocimetry
… the turbulent entrainment of fluid from the recirculation region of the three-dimensional ice simulation separation bubble flowfield. These vortices were generated by a streamwise-vortex instability excited by roughness along the three-dimensional ice simulation and produced spanwise-cell …
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Investigation of Fuel Geometry and Solid Fuel Combustion for Solid Fuel Ramjets
… the reacting flow and identified key reaction regions relevant to flame holding. Observations of the spatial regression rate show similar trends to the initial experiments, revealing a large increase in regression rate associated with the cavity corner. The regression rates and observations …
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Investigation of liquid fuel jet injection into a simulated subsonic "dump" combustor
… flow studies showed details of the flow in the recirculation region behind the step. The injectant for these cold flow studies was selected as water, which was injected transversely to the air flow 1.0 in. and 0.5 in. upstream of the step at various flow rates. It was found that both the …
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Flow characteristics of a transverse water jet into an unconfined water channel
… jet from the bottom of a channel, induces a recirculation region at the upstream side of the channel; however, with a transverse jet in this study no upstream recirculation region was observed. The strength of the reverse flow region was influenced by the degree of blockage of the crossflow …
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Separation of liquid-vapor two-phase flow in headers of microchannel condensers
… efficiency deteriorates dramatically when the recirculation region elevates up to the top of the header, with increasing inlet flow rate and/or quality. Potential design options to improve two-phase separation are discussed. The objective should be to avoid or at least delay the recirculation …
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Real-Time Prediction of Lean Blowout using Chemical Reactor Network
… stirred reactors (PSRs) in series with a recirculation pathway, the model inputs include real-time reactor temperature measurements and mass flows of fuel and air. The goal of the CRN is to provide a computationally fast means of interpreting measurements in real time with regard to …
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Time-Resolved PIV Measurements of Ship Airwakes with Quartering Winds
… velocity magnitudes. The flight deck recirculation region decreased in size and became asymmetric for both quartering wind cases. Different flight deck vortical structures were found, indicating a difference within the flow field based on the yaw angle. A spectral analysis showed the …
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3-D flow and performance of a rocket pump inducer at design and off-design flow rates
… boundary layers. The tip leakage flow formed a recirculation region, a toroidal shaped vortex at the tip leading edge of the blades. The associated backflow forms a blockage that varies with flow rate. The thermodynamic performance was evaluated by calculating the contributions to pressure rise, …
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The aeroacoustics response and shear layer dynamics of confined cavities subject to low Mach number turbulent flow
… unique behaviour due to the interference of the recirculation region within the cavity, ultimately modifying the symmetry of the shear layer. Particle image velocimetry (PIV) measurements present spatial characteristics of the shear layer dynamics, revealing improved flow modulation with …
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