Semester

Summer

Date of Graduation

2009

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

Donald D Gray

Abstract

An aquaculture raceway is a water carrying, open channel with a rectangular cross-section used to raise fish. The first objective of this research is to measure the flow characteristics within a small section of an aquaculture raceway system called the quiescent zone, and determine if the flow through the quiescent zone contains two-dimensional, fully developed, turbulent open channel flow characteristics. If any discrepancies exist, the cause or causes of the discrepancies are to be analyzed. The measured flow characteristics are intended to improve previous measurements taken in the quiescent zone of a rectangular aquaculture raceway system. The second objective is to design an efficient non-labor intensive system for removing solid particles from the bottom of a quiescent zone. The flow through the raceway at Dogwood Lake, West Virginia, contains subcritical flow and has a Reynolds number of approximately 2 x 104, which indicates that the flow is mildly turbulent.;The first objective is accomplished by using an Acoustic Doppler Velocimeter (ADV) to measure velocities in three dimensions at a point. The velocities measured by the ADV are sampled at 10 Hz and averaged over a 360 second time interval in order to calculate a mean velocity and other statistical parameters in each direction. ADV measurements allow for flow characteristics such as mean velocity profiles, turbulence intensity (TI) profiles, and Reynolds stress profiles to be measured within the quiescent zone. The mean velocity, turbulence intensity, and Reynolds stress profiles seem to contain two-dimensional, fully developed, turbulent characteristics in certain respects, but vary dramatically in others. The large eddy range, inertial subrange, and dissipation range are difficult to segregate in several measurements of the energy spectrum. Discrepancies between these measurements and two-dimensional, fully developed, turbulent open channel flow are due to disturbances and geometry limitations of the raceway. It was found that a disturbance caused by a small meshed screen separating the fish from the quiescent zone may reduce turbulence intensity values in the quiescent zone.;The second objective is accomplished by determining several possibilities for a cleaning mechanism and choosing the mechanism that best fits the constraints and limitations at Dogwood Lake. Two mechanisms were constructed and tested in one quiescent zone at Dogwood Lake. The first constructed cleaning mechanism was the sloped false bottom (SFB). The SFB is a false bottom with sloped walls used to collect solids into a concentrated area. A pre-existing standpipe system is used to remove the solids from the concentrated area. The second constructed mechanism is the siphon system (SS). The SS is powered by a siphon connected to a false bottom that evenly distributes suction throughout the false bottom. Both mechanisms failed to clean the entire bottom thoroughly.

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