Author
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Hanson, Gregory |
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Robinson, Kerry |
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Submitted to: American Society of Civil Engineers Hydraulic Conference Proceedings
Publication Type: Proceedings Publication Acceptance Date: 8/14/1995 Publication Date: N/A Citation: N/A Interpretive Summary: There is a need for all types of information on turbulence in water, not only as checks on existing data, but also to provide new information for various flow conditions. Hydraulic stresses at the boundary of water flow are often presented as mean values whereas, in reality these stresses fluctuate over a wide range. The nature of turbulence fluctuations has practical implications to engineering problems such as erosion, scour, and sediment transport. In this paper the characteristics of these fluctuations were measured and reported for flow in two very different environments, a submerged impinging jet and a pipe. The overall results indicated a higher level of turbulent fluctuations along the flow boundary in the jet environment than was observed in the pipe environment. Pipe flow is often used as a means to calibrate instrumentation necessary for measuring boundary stress fluctuations in other environments. Therefore, it is necessary to understand the differences of the turbulent nature between the calibrating environment and the flow environment of interest. Technical Abstract: In this paper measurements are presented of the stochastic nature of turbulence at the boundary of a pipe and the boundary of a submerged impinging jet. A comparison of the stochastic nature of the voltage measurements from the constant temperature anemometer for these two environments is presented. The overall results indicate a higher activity of local turbulence in the jet environment. It was concluded that comparison of mean shear stress measurements, due to different hydraulic conditions, may lead to erroneous conclusions if the variance, which depends on the hydraulic conditions is not considered. |
