Simplified equations of fluid mud motion, which is described as Bingham-Plastic model under waves and currents, are presented by order analysis. The simplified equations are non-linear ordinary differential equations ...Simplified equations of fluid mud motion, which is described as Bingham-Plastic model under waves and currents, are presented by order analysis. The simplified equations are non-linear ordinary differential equations which are solved by hybrid numerical-analytical technique. As the computational cost is very low, the effects of wave current parameters and fluid mud properties on the transportation velocity of the fluid mud are studied systematically. It is found that the fluid mud can move toward one direction even if the shear stress acting on the fluid mud bed is much smaller than the fluid mud yield stress under the condition of wave and current coexistence. Experiments of the fluid mud motion under current with fluctuation water surface are carried out. The fluid mud transportation velocity predicted by the presented mathematical model can roughly match that measured in experiments.展开更多
The mass transport in a thin layer of non-Newtonian bed mud under surface waves is examined with a two-fluid Stokes boundary layer model. The mud is assumed to be a bi-viscous fluid, which tends to resist motion for s...The mass transport in a thin layer of non-Newtonian bed mud under surface waves is examined with a two-fluid Stokes boundary layer model. The mud is assumed to be a bi-viscous fluid, which tends to resist motion for small-applied stresses, but flows readily when the yield stress is exceeded. Asymptotic expansions suitable for shallow fluid layers are applied, and the second-order solutions for the mass transport induced by surface progressive waves are obtained numerically. It is found that the stronger the non-Newtonian behavior of the mud, the more pronounced intermittency of the flow. Consequently, the mass transport velocity is diminished in magnitude, and can even become negative (i.e., opposite to wave propagation) for a certain range of yield stress.展开更多
An attempt is made to analyse some lubrication characteristics of rigid cylindrical asymmetric rollers under adiabatic and isothermal boundaries with rolling and sliding motion lubricated by a non-Newtonian incompress...An attempt is made to analyse some lubrication characteristics of rigid cylindrical asymmetric rollers under adiabatic and isothermal boundaries with rolling and sliding motion lubricated by a non-Newtonian incompressible Bingham plastic fluid under the behaviour of line contact.Here the lower surface is considered to move quicker than that of the upper surface;and the Roelands viscosity model is considered and assumed to depend upon the fluid pressure and the mean film temperature.The governing equations for fluid flow such as equations of motion with continuity and the momentum energy equation are solved using Runge-Kutta forth order and MATLAB is employed to solve these equations.Through graphs and tables for Newtonian and non-Newtonian fluids,the several crucial bearing characteristics including velocity,pressure,viscosity,mean temperature,load and traction are examined and a significant change is observed among them.The findings presented here are qualitatively consistent with the existing literature.展开更多
基金financially supported by the 300000DWT Waterway of Lianyungang Harbor Construction Projectthe National Natural Science Foundation of China(Grant No.11272116)
文摘Simplified equations of fluid mud motion, which is described as Bingham-Plastic model under waves and currents, are presented by order analysis. The simplified equations are non-linear ordinary differential equations which are solved by hybrid numerical-analytical technique. As the computational cost is very low, the effects of wave current parameters and fluid mud properties on the transportation velocity of the fluid mud are studied systematically. It is found that the fluid mud can move toward one direction even if the shear stress acting on the fluid mud bed is much smaller than the fluid mud yield stress under the condition of wave and current coexistence. Experiments of the fluid mud motion under current with fluctuation water surface are carried out. The fluid mud transportation velocity predicted by the presented mathematical model can roughly match that measured in experiments.
基金The work was supported by CRCG Research Grant 10203302 awarded by the University of Hong Kong,and Grants HKU 7117/99E and HKU 7081/02E awarded by the Research Grants Council of the Hong Kong Special Administrative Region
文摘The mass transport in a thin layer of non-Newtonian bed mud under surface waves is examined with a two-fluid Stokes boundary layer model. The mud is assumed to be a bi-viscous fluid, which tends to resist motion for small-applied stresses, but flows readily when the yield stress is exceeded. Asymptotic expansions suitable for shallow fluid layers are applied, and the second-order solutions for the mass transport induced by surface progressive waves are obtained numerically. It is found that the stronger the non-Newtonian behavior of the mud, the more pronounced intermittency of the flow. Consequently, the mass transport velocity is diminished in magnitude, and can even become negative (i.e., opposite to wave propagation) for a certain range of yield stress.
文摘An attempt is made to analyse some lubrication characteristics of rigid cylindrical asymmetric rollers under adiabatic and isothermal boundaries with rolling and sliding motion lubricated by a non-Newtonian incompressible Bingham plastic fluid under the behaviour of line contact.Here the lower surface is considered to move quicker than that of the upper surface;and the Roelands viscosity model is considered and assumed to depend upon the fluid pressure and the mean film temperature.The governing equations for fluid flow such as equations of motion with continuity and the momentum energy equation are solved using Runge-Kutta forth order and MATLAB is employed to solve these equations.Through graphs and tables for Newtonian and non-Newtonian fluids,the several crucial bearing characteristics including velocity,pressure,viscosity,mean temperature,load and traction are examined and a significant change is observed among them.The findings presented here are qualitatively consistent with the existing literature.
