Gorban V. Modeling of non-stationary interactions of bodies in flows

The thesis is devoted to the physical effects and phenomena that arise under motion of some bodies in water or when a body moves near flow boundaries. The main result of the work consists in both development theoretical methods for simulation of body interactions in fluid flows and definition of mechanisms and characteristics of those. The non-stationary dynamic characteristics of wings and cylindrical bodies are obtained when they interact with boundary irregularities. Researches of the lateral force and torsion moment acting on vessels under their passing or opposing motion and when the coastline has irregularities are executed. Viscous interaction of two square cylinders placed either in a side-by-side arrangement or in tandem was studied. The primary role when generating flow patterns and loads in such systems was revealed to play geometry parameters, particularly the gap width between bodies. The new schemes of flow control near bluff bodies are proposed. They are based on generation of stable vertical zones in the near-wall flow with help of special surface irregularities. The relations for hydrodynamic forces acting on the circular cylinder near a rough surface are derived, they point out on body attracting to the bottom under its intensive roughness. Hydrodynamic interaction between bluff bodies and free surface is considered theoretically and experimentally. New numerical models of non-stationary motion of cable towing systems are developed and dynamic characteristics of such systems are determined at constant and changing cable length.