Finite Element Techniques for Fluid Flow

196 INVISCID FLUIDS

b to c and c to b'. At b, the velocities are small (pressure

large) ;

at c,

the velocities are large (pressure small) and at b', the velocities are

small again (pressure large). Then aside from the main current the

liquid will tend to travel from b' to c and because of this the turbu-

lence behind the object increases. If the velocity increases the

turbulent zone will progress as the streamlines will leave an empty

space behind the obstruction. In this empty space, the water

vaporises and some of its particles are transported to regions of

high pressure where they are suddenly compressed. This com-

pression produces particle ...