Distribution of two-phase liquid parameters along the boundary of the moving ship’s hull at different values of the volumetric gas concentration

Abstract

In this paper, in contrast to the known methods, the forces acting on a moving ship are determined with account for gas bubbles near the ship's hull. The paper presents a mathematical model for water flow around a ship, considering the interaction between the ship's hull and the boundary layer with account for gas bubbles in it. We propose analytical methods to determine the parameters of liquid flowing around the ship with consideration for its two-phase nature. We also present a method for the numerical solution of the system of constitutive equations associated with the proposed model as well results of those calculations. In the course of the study, we built dependences for velocity components, distribution of liquid pressure and density in the boundary layer along the outer boundary of the ship for different values of the volumetric gas content. The availability of gas leads to compressibility of the liquid, which reduces pressure around the ship's hull. When the ship moves, the liquid density and pressure around it decrease. The influence of gas bubbles on the mixture pressure and density reduction grows with the ship subsidence: the greater the velocity of the flow moving along the ship's hull, the greater the pressure reduction and, therefore, the greater the ship's subsidence.