INVESTIGATIONS ON WATER CIRCULATION IN ANIMAL SEA-WATER BASINS – ON THE EXAMPLE OF SEALS’ BREEDING POOLS

Abstract

This paper presents general comments concerning investigations on water circulation in animal breeding pools containing sea water. As an example are given results of computer simulation of water circulation in seals’ breeding pools situated in Marine Station at Hel, belonging to Oceanographic Institute, Gdansk University. A mathematical model of three main pools was prepared with taking into account their inflow and outflow water supply points. Next, the object indication (tracer) tests were done with the use of mathematical modelling as well as in-situ measurements. For description of flow field in steady conditions a simplified model of 2D flow in the form of Helmholtz biharmonic equation of stream function, recalculated then into velocity vector components, was used. The equation, supplemented with appropriate boundary conditions, was solved numerically by using the finite differences method. The spreading of a substance dissolved in water (tracer) was analyzed by solving 2D equation of transient advecting - dispersing transport. To solve it the finite volumes method was applied. The applied model was verified by conducting the indication tests with the use of the rhodamine WT as a tracer. The obtained results made it possible to reconstruct water circulation within the seals’ pools and identify stagnation zones in which water circulation may be made difficult.