Investigations on a flat, square plate at high incidence in a low speed flow.

(1988) Investigations on a flat, square plate at high incidence in a low speed flow. Masters thesis, King Fahd University of Petroleum and Minerals.


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The phenomenon of abrupt and large change in normal force occurring at some high, critical incidence on low-aspect ratio plates in incompressible flow is of considerable interest, as such plates have practical applications, e.g. as missile wings and control surfaces, shiprudders, heliostats, and antennas. This change in normal force at high incidence has its origin in a change of the flow field. A flat, square, sharp-edged plate was investigated in low-speed flow at subscritical incidence (i.e. a < 30 degree). The flow field was studied using flow visualizations, applying an electromagnetic analogy, and using a simple theoretical approach. The flow visualization tests were carried out in the 0.8M* 1.1m low speed wind tunnel of the K.F.U.P.M. Aeronautical Laboratory. Flow patterns were obtained by means of surface oil-flow technique, smoke flow visualizations (with flow illumination by laser-light plane) and fufts of wool and paper. The smoke flow visualizations were also recorded on video tape. In experiments using the electromagnetic analogy, vortex flow was simulated by means of the magnetic field of a current-carrying wire and uniform-flow simulation was achieved by the uniform magnetic field inside a current-carrying cylindrical coil. "Flow patterns" were made visible by means of iron filings. A simplified theoretical model was used to describe some characteristic features of the flow, the computations were performed on the IBM 3033 central computer of K.F.U.P.M. The flow visualization tests in the wind tunnel led to a conjectured, complex flow pattern on the suction side of the plate. The experiments using the electromagnetic analogy, and the results of theoretical modelling of the flow supported the conjectured flow pattern and gave additional information about the relative vortex strengths of the vortex configuration. On the pressure side of the plate, the surface flow visualization tests revealed a degenerate node.

Item Type: Thesis (Masters)
Subjects: Mechanical
Department: College of Engineering and Physics > Mechanical Engineering
Committee Advisor: Stahl, Wolfgang H.
Committee Members: Otis, Davis R. and Stuff, Ing. Ronald Stuff and Budair, Mohammad O.
Depositing User: Mr. Admin Admin
Date Deposited: 22 Jun 2008 13:45
Last Modified: 01 Nov 2019 13:49