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« เมื่อ: มกราคม 16, 2010, 02:45:44 PM »

2-D hydrodynamic model simulating paddlewheel-driven circulation in rectangular shrimp culture ponds

Yun Ho Kanga,*, Moon Ock Leeb, Sang Duk Choic, Yong-Sik Sind
a Aquaculture Research Center, Yosu National University, Yeosu 550-749, South Korea
b Division of Ocean System, Yosu National University, Yeosu 550-749, South Korea
c Division of Aqualife Science, Yosu National University, Yeosu 550-749, South Korea
dDepartment of Marine Environmental Engineering, Mokpo National Maritime University,
Mokpo 530-729, South Korea

Aquaculture 231 (2004) 163–179
Received 21 February 2003; received in revised form 13 August 2003; accepted 18 August 2003

Abstract
This study surveyed and simulated paddlewheel-driven circulation in rectangular shrimp culture
ponds. Paddlewheels are widely used for highly intensive culture ponds to improve reaeration and
circulation. From flow measurements, the major circulation pattern was found to be a single large
eddy with strong and weak flows, respectively, along the pond bank and the eddy centre. A twodimensional depth integrated numerical model was refined to represent the circulation, with
acceleration of the paddlewheel given as a shaft force divided by the water mass driven away by
paddlewheel blades. The model was applied to a pond F, deploying a single paddlewheel and
calibrated for a mass correction factor a in the range 15–20 and for a dimensionless eddy viscosity
constant c of 6. The model was then applied to two ponds A and B, with four paddlewheels deployed
at four corners, respectively. The measured and predicted currents were processed using regression
analysis to show both the correlation coefficients and gradients; i.e. 0.9067, 1.0393 for direction and
0.6691, 0.8307 for speed in pond A and 0.8269, 1.0075 for direction and 0.7138, 0.9362 for speed in
pond B. It was concluded from these results that the model could deal with the paddlewheel-driven
jet flow in a simple way to that of using a mass correction factor a, first shown in this study and
giving good prediction. Therefore, the model provides a useful tool to predict horizontal circulation
and an insight into the circulation-related sedimentation and water quality in shrimp ponds.

D 2004 Elsevier B.V. All rights reserved.

Keywords: Paddlewheel; Pond circulation; Numerical model; Mass correction factor
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