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Type of Document	Dissertation
Author	Reihman, Thomas Charles
URN	etd-09272002-153158
Persistent URL	http://resolver.caltech.edu/CaltechETD:etd-09272002-153158
Title	Laminar flow over transverse rectangular cavities
Degree	PhD
Option	Mechanical Engineering
Advisory Committee	Advisor Name Title unknown Committee Member
Keywords	none
Date of Defense	1967-05-19
Availability	unrestricted
Abstract NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. An experimental investigation was conducted on the laminar flow of water over transverse rectangular cavities. Most of the cavities were square ranging in size from 1/8 in. to 1 in. The flow over the cavities was observed for an [epsilon]* range of from 16 to 400. The quantity [epsilon]* may be regarded as a Reynolds number for the cavity. It is defined as [...] where [epsilon] is the cavity depth, [...] is the shear velocity, and [...] is the kinematic viscosity of the fluid. The desired flow approaching the cavities was obtained one foot from the leading edge of a flat plate suspended in an open surface water tunnel at free stream velocities from 0.125 to 0.75 ft/sec. Visual studies, instantaneous velocity measurements, and velocity profile determinations confirmed that the flow was laminar. The velocity measurements were obtained by means of a hot-film anemometer. The primary goal of the investigation was to determine whether the strong random mass-exchange activity observed in identical cavities in turbulent flow in the same [epsilon]* range was due to an inherent instability of the cavity flow or due to the excitation from turbulent fluctuations at the cavity opening. As the present experiments showed no such strong mass exchange, it was concluded that the latter mechanism was indeed the essential factor. In conjunction with these studies the flow patterns in the cavities were examined by visualization techniques and cavity velocity measurements were made. The cavity vortex velocities were found to be less than 8 percent of the free stream velocity in the range of [epsilon]* examined. In addition a laminar oscillation was observed in the shear layer at the cavity opening and its frequencies are reported. Photographic material on pp. 93-133 are essential and will not clearly reproduce on Xerox copies. Photographic copies should be ordered.
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