were able to show for a high pressurized flow thoug haven turinozzle with applied back-pressure first a decrease of visible cavitation occurrence until cavitation was totally suppressed a thigh back-pressures.Consequently,the vapor contention and down stream of the constriction decreases as well.Actual measurements in a rectangular micro-channel with a modified μ-PIV method show impressively how sensitive cavitation in duced vapor content responds on applied pbp