Engineering Commons^™

Near-Wake Flow Dynamics Of A Horizontal Axis Wind Turbine, Pooyan Hashemi Tari

Electronic Thesis and Dissertation Repository

Experiments have been conducted in a large wind tunnel set-up in order to study the flow structures within the near-wake region of a horizontal axis wind turbine. Particle Image Velocimetry (PIV) has been employed to quantify the mean and turbulent components of the flow field. The measurements have been performed in multiple adjacent horizontal planes in order to cover the area behind the rotor in a large radial interval, at several locations downstream of the rotor. The measurements were phase-locked in order to facilitate the re-construction of the three-dimensional flow field. Acquiring uniform particle distribution in the measurement planes as …

The Near Wake Of A European Starling, Adam J. Kirchhefer

Electronic Thesis and Dissertation Repository

The wake of a freely flying European starling (Sturnus vulgaris) was measured using high speed, time-resolved, particle image velocimetry, simultaneously with high speed cameras which imaged the bird. These measurements have been used to generate vector maps in the near wake that can be associated with the bird’s location and wing configuration. A kinematic analysis has been performed on select sequences of measurements to characterize the motion of the bird, as well as provide a point of comparison between the bird of the present study and other birds or flapping wings. Time series of measurements have been expressed …

Numerical Investigation Of Highly Curved Turbulent Flows In Centrifugal Compressors And In A Simplified Geometry, Kevin J. Elliott

Electronic Thesis and Dissertation Repository

Curvature effects are investigated in terms of a recently developed curvature corrected turbulence model in turbomachinery applications. Two centrifugal compressor stages and a curved geometry modelled after a centrifugal impeller are simulated using the curvature corrected SST (SST-CC) turbulence model. This work improves the understanding of how the SST-CC model predicts curvature effects. An analysis of the SST-CC production multiplier in both centrifugal cases reveals that the model is appropriately accounting for curvature effects, showing increased production near concave surfaces and decreased production near convex surfaces. This correlates well with the simplified geometry results and demonstrates that the simplified geometry …

Experimental And Numerical Study Of Flow Structures Associated With Low Aspect Ratio Elliptical Cavities, Taravat Khadivi

Electronic Thesis and Dissertation Repository

The flow regimes associated with a 2:1 aspect ratio, elliptical planform cavity in a turbulent flat plate boundary layer have been systematically examined for various depth/width ratios (0.1 to 1.0) and yaw angles (0° to 90°), using a combination of wind tunnel experiments (involving Particle Image Velocimetry and helium bubble visualization) and Computational Fluid Dynamics (CFD) simulations (employing three- dimensional steady calculations with the Reynolds Stress model turbulence closure). Satisfactory agreement has been found between the results using the two methods, indicating that the steady numerical simulations can be a cost-effective tool to predict the mean flow features.

The flow …