Characterization of the Far-Wake of a 6:1 Prolate Spheroid
Abstract
Even with the dramatic advances in computational power seen in the last decades, Computational Fluid Dynamics (CFD) models are as yet unable to predict transition, separation, and wake development for fluid flow over three-dimensional bodies to the desired level of accuracy in an acceptable amount of time. Without the ability to predict forces and moments experienced by the body, critical parameters such as drag and loads on control surfaces for air and water-borne vehicles cannot be predicted. The prolate spheroid has long been a popular body upon which to verify CFD models because of its simple geometry and three-dimensional flow field. Advances in computational speed and experimental capabilities have prompted a renewed interest in related research. An experiment was conducted in the large towing tank facility of the U.S. Naval Academy, using a 6:1 prolate spheroid, measuring 54 in. (1.4 m) in length and 9 in. (0.23 m) in diameter. The spheroid model was inclined by 15 relative to the undisturbed free surface, and towed at speeds yielding length-based Reynolds numbers from 0.5-4.2106. The results from the 0.5106 case are presented in the present discussion. A stationary stereo particle image velocimetry (SPIV) system was designed for the experiment and used to provide two-dimensional velocity maps in two spatial-dimensions (2C2D). These time histories show the trajectory of the wake as it leaves the tail of the model, the expansion of the wake width, the size, strength, and position of the primary vortical structures shed into the wake. These results will inform follow-on studies focused on measuring turbulent quantities in the far wake.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 06, 2020
- Accession Number
- AD1136692
Entities
People
- Jonathan P. Peck
Organizations
- United States Naval Academy