发明名称 |
Method for analyzing friction reduction effects of bubbles in friction-reducing ship |
摘要 |
A method is provided for analyzing the effects of bubbles on skin-friction reduction in a ship cruising in a bubbly flow field. A shear stress decrementτt produced by a bubble in a flow field is obtained in a high frequency band region, in which a product of a bubble time-constant T and a turbulence frequency omegaL in a flow field is sufficiently greater than 1, based on a resistive force DELTARv acting on a bubble derived from the bubble movements in a fluid flow direction along a ship surface and in a direction at right angles to a ship wall surface. Assuming that the shear stress a decrement is generated by a decrease in a gas mixing length, an expression for the operative wall constant kappa1 for bubbly flow including a parametric bubble diameter db is derived. Based on an expression relating the operative wall constant kappa1 and a local friction factor Cf in bubbly flow, and an expression relating the normal wall constant kappa in non-bubbly flow and a local friction factor Cf0 in non-bubbly flow, an analytical solution is obtained for a skin-friction ratio Cf/Cf0.
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申请公布号 |
US6324480(B1) |
申请公布日期 |
2001.11.27 |
申请号 |
US19990317326 |
申请日期 |
1999.05.24 |
申请人 |
ISHIKAWAJIMA-HARIMA HEAVY INDUSTRIES CO., LTD.;KATO HIROHARU |
发明人 |
TAKAHASHI YOSHIAKI;YOSHIDA YUKI;KATO HIROHARU |
分类号 |
B63B1/38;B63B9/00;F15D1/12;G01N13/02;G01N19/02;(IPC1-7):G01F17/00;G01F23/00;G01N11/00 |
主分类号 |
B63B1/38 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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