FIRST STEPS IN THE CALCULATION OF STREAMLINES CLOSE TO THE STAGNATION POINT BY NUMERICAL-METHODS IN THE GENERAL 3-DIMENSIONAL POTENTIAL FLOW

Stagnation points are of fundamental importance in tracing the system of streamlines which define a closed form. For the complicated distributions of hydrodynamic singularities only numerical methods have to be applied for solving of problem. The velocity components vanish at the stagnation point and the streamline differential equations take the indeterminate form which results the impossibility of starting step of numerical integration algoritm. Three pairs of slopes, which represent the roots of two symmetric quadratic equations in two unknowns, show that streamline entering the stagnation point branches at right angles. These three pairs of slopes define the reference system whose axes are principal - axes of the rate of deformation tenser.