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The work is focused on the shape of velocity profiles of viscous liquid (water) in contact with hydrophobic surface. A demonstration is done on an example of liquid flow between two parallel plates. The solution is carried out at both the constant and variable viscosity of the liquid near the wall. The slip boundary condition of the liquid on the wall is expressed by the coefficient of adhesion and the shear stress on the wall. As a result, presented are the shapes of the velocity profiles in dependence on the coefficient of adhesion and the slip velocity on the wall. This solution is for laminar flow.

This paper deals with the problem of identification of added effects of incompressible Newtonian fluid that impacts on the rigid journal performing translational motion. It considers two degrees of freedom. The axial motion of the rigid journal was neglected. It assumes small oscillations and linear model. The task was solved for two geometrical configurations of the computational domain. In the first variant of geometry, there is no flow between the bases of journal and stator. The second variant of geometry also allows liquid to flow in space between the bases of journal and stator. The introduction describes the mathematical model for the identification of added mass, damping and stiffness matrices. On the basis of the mathematical model and computational modeling of velocity and pressure fields using CFD, the force components are determined. From there, the mentioned matrices are determined depending on the eccentricity of the rigid journal.

The work presents a Coanda effect in areas with different geometry and surface properties. Surfaces with hydrophilic and hydrophobic properties are considered. Coanda effect is demonstrated by the velocity fields shape. The velocity field structure is shown both on the basis of the experiment and using computational modeling. The Coanda effect principle is explained on the continuity equation for an incompressible fluid bases.

The article presents a mathematical model of the interaction between a rotating shaft and an incompressible fluid. The mathematical model includes the axially traversed hydrodynamic sealing gap of hydraulic machines. A method is shown for the identification of additional effects of the fluid acting on the rotor of the machine. The interaction is expressed by matrices of stiffness and damping. The shown problems were solved with the assumption of a hydrophilic surface with zero velocity vectors on the motionless surface and zero relative velocity vectors on the moving surface. Owing to the technological progress in the area of surface layers it is not necessary anymore to assume the surface of the solid/liquid interaction to be hydrophilic. It is possible to generalize the solution of hydrodynamic problems and assume hydrophobic character of the surface in the solid/liquid interaction. That means slipping of the liquid on the hydrophobic surface. Comparison of the effect of the surface properties is shown ...

This contribution is focused on the analysis of dynamic behavior of elastic continuum moving in liquid. The method of solution is demonstrated on the non-stationary movement of a bar in a real, incompressible liquid. The principle of the solution is based on the modal transformation of the bar and discrete process using the finite element method (FEM). The problem is in general non-linear. However, the method introduced in this contribution allows the solution of the problem in time steps. The solution is based upon a certain substitution which provides gradual separation of the movement of liquid and the movement of the bar. This substitution is entered analogously on the finite element and is dependent on the normal coordinates. The result is a tensor of additional effects.