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Pressure fluctuation of unsteady flow in waterjet |
College of Naval Architecture and Marine Power, Naval University of Engineering, Wuhan, Hubei 430033, China) |
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Abstract Based RANS equations and SST turbulent model,the unsteady flow in waterjet was numerically simulated. The mesh independence analysis shows that calculated power and thrust are well consistent with experiment data with maximal error less than 4%. Under the conditions of ratedrotationalspeed and selfpropulsion, the timedomain and frequencydomain of pressure fluctuation at inlet and outlet of impeller, middle and outlet of stator were investigated. The results show that the maximum amplitude of pressure fluctuation appears at impeller inlet. The pressure fluctuation at impeller inlet from 80° to 140° radial direction is higher than that at other locations due to the nonuniform inflow. At both inlet and outlet of impeller, the peak frequency occurs at impeller blade passing frequency with fluctuation amplitude gradually increasing from hub to tip. Under the ratedrotationalspeed conditions, pressure fluctuation at impeller inlet of ratedshipspeed is the weakest. Under the selfpropulsion conditions, peak frequency and waterjet rotational speed present a linear relationship, and the pressure fluctuation intensity is increased with the ship speed.
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