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Showing 1 to 20 of 20 for “"Cylinder Wake"”.
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Electro-magnetic control of cylinder wake
… closed-loop control algorithms for manipulating wake flows past a solid cylinder in an electrically low-conducting fluid (e.g. seawater). The intent is to avoid both vortex shedding and flow separation from the body. It is desired to reduce the mean drag significantly and prevent the lift from …
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The Two Point Correlation Structure of a Cylinder Wake
… time correlation function was measured in the wake of an untripped circular cylinder at a Reynolds number of 60 000. This correlation serves as the complete inflow boundary condition for an open rotor ingesting inhomogeneous turbulence. An important aspect of the turbulence ingestion problem is …
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Three-dimensional turbulence mechanisms in a supersonic separated/reattaching longitudinal cylinder wake
… of the turbulence structure in the near-wake of a blunt-based cylinder aligned at zero angle-of-attack in a Mach 2.49 freestream. Particular emphasis is placed in this work on the identification of turbulence mechanisms in the flow regions both upstream of, and in the immediate vicinity …
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Numerical Simulation of Plasma-Based Actuator Vortex Control of a Turbulent Cylinder Wake
… to investigate the mechanics of the turbulent wake of a circular cylinder that is controlled by a plasma actuator. The numerical investigation implements a straightforward moving wall boundary condition to model the actuator's effects on the flow. Validations of the moving wall for this …
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The drag and lift characteristics of a cylinder placed near a plane surface
… experimentally determined for a right circular cylinder located near a plane surface and placed in a cross flow of air. Parametric studies were carried out for Reynolds numbers varying from 90,000 to 250,000, three plate lengths and a variety of cylinder to plate spacings. The variation of the …
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The effects of periodic wake disturbances on flat-plate turbulent boundary layers
… to upstream blades creating unsteady periodic wakes that interact with the boundary layer and free stream flows about downstream blades. This study modelled these flow conditions, with circular cylinders periodically traversing in front of a turbulent flat plate boundary layer inside a low …
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Inhomogeneous, Anisotropic Turbulence Ingestion Noise in Two Open Rotor Configurations
… inflows were studied: a rotor ingesting the wake of an upstream cylinder and a rotor ingesting a thick axially symmetric boundary layer from an upstream centerbody. In both cases, the undisturbed inflow was measured without the rotor present in order to characterize the inflow, in particular …
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Modification of Blade-Vortex Interactions Using Leading Edge Blowing
The interaction of an unsteady wake with a solid body can induce sizable loading of the structure, which has many detrimental side effects in both the structural and acoustic senses. These interactions are ubiquitous in nature and engineering. A flow control technique is sought to mitigate this …
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Turbulence Modeling and Simulation of Unsteady Transitional Boundary Layers and Wakes with Application to Wind Turbine Aerodynamics
… The model problem consists of a circular cylinder for generating coherent unsteadiness and a downstream airfoil in the cylinder wake. The cylinder flow is subcritical, with a Reynolds number of 64,000 based upon the cylinder diameter. The quantitative dynamics of vortex shedding and …
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Heat Transfer to Arrays of Oscillating Impingement Jets
… that the interaction of impingement jets with cylinder wake can improve the intensity and uniformity of heat transfer. The goal of this study is to computationally investigate the heat transfer characteristics resulting from an array of cylinder jets, capturing the interaction of neighboring …
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Flow separation control with rotating cylinders
… relevant, two-dimensional flow past a circular cylinder at moderate sub-critical Reynolds numbers (37,000 and 52,000 in experiment and 100 and 10,000 in simulation). The active control injects momentum into the boundary layer via the moving surfaces of two small control cylinders located near …
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Experimental Investigation of the Active Flow Control on a Two-Dimensional Wind Turbine Airfoil
… the fluctuating loading generated by an upstream cylinder wake was reduced by up to 12% using a proportional closed loop control algorithm at 27 degree angle of incidence. Under the same unsteady freestream conditions, the averaged lift coefficient at 19 degree angle of incidence was enhanced by …
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Propulsion through wake synchronization using a flapping foil
… through synchronization with an incoming Karman wake for both fish and mechanical flapping foils. Rainbow trout (Oncorhynchus mykiss) swimming within a flow channel voluntarily positioned themselves 4D downstream from a 2" D-section cylinder, and synchronized with the cylinder wake in both …
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Three dimensional topology and structural differences in the turbulent wake of cantilevered square and circular cylinders protruding thin boundary layers
… around cantilevered circular and square-section cylinders to investigate the effects of the cylinder geometry and the boundary layer state on the wake structures and flow topology. Detailed velocimetry results are presented in the wake of circular and square cylinders protruding a thin laminar …
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Simulations of droplet dispersion in the wakes of cylinders and icing tunnel spray bars
Simulations of droplet dispersion behind cylinder wakes and downstream of icing tunnel spray bars were conducted. In both cases, a range of droplet sizes were investigated numerically with a Lagrangian particle trajectory approach while the turbulent air flow was investigated with a hybrid …
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Lagrangian Visualization and Real-Time Identification of the Vortex Shedding Time in the Wake of a Circular Cylinder
<p>The flow around a circular cylinder, a canonical bluff body, has been extensively studied in the literature to determine the mechanisms that cause the formation of vortices in the cylinder wake. Understanding of these mechanisms has led to myriad attempts to control the vortices either to …
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On the Application of Rotating Cylinders to Micro Air Vehicles
… into the feasibility of using rotating circular cylinders as the primary means of generating lift for the class of very small (0.15 m maximum dimension, 50 g weight) unmanned aircraft known as Micro Air Vehicles (MAV) has been carried out. It is hoped that such a design would be able to exploit …
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Propeller Noise Prediction of an Urban Air Mobility Vehicle in Urban Environment
… complex, unsteady aerodynamic environments where wake interactions, gust and turbulence significantly affect both performance and noise generation. Understanding these mechanisms is critical for developing quieter and more efficient eVTOL systems that meet future community noise and certification …
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An Experimental Spatio-Temporal Analysis of Separated Flows Over Bluff Bodies Using Quantitative Flow Visualization
… unsteady turbulent flow fields such as the wakes of bluff bodies, a Digital Particle Image Velocimetry (DPIV) system was developed. This system allows non-intrusive two-dimensional and time varying velocity measurements. Software and hardware modifications necessary to enhance the …
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Simulation, Modeling, and Characterization of the Wakes of Fixed and Moving Cylinders
… produce the lift and drag coefficients on a cylinder or a cylinder-like structure. We introduced an improved wake oscillator for the lift, which combines the van der Pol and Duffing equations. We proposed a two-term quadratic model that relates the drag and lift coefficients, which reproduces …