STUDIES ON THE FLOW CHARACTERISTICS OF THE HIGH SPEED WATER JETS IN AIR: THE FLOW CHARACTERISTICS OF CONTINUOUS WATER JETS - 1.

For the purpose of considering the performance of a nozzle of a hydraulic cutting device and mechanism of the hydraulic fracturing, the authors investigate theoretically and experimentally the flow characteristics of continuous water jets issuing into a quiescent air ambient. The analytical relations of momentum theory are proposed on experimental findings for the width of jet spread. The pattern of the jet spread is proved by means of the electric method, the Pitot tube method, the photographic method. Further the jet velocity of center line is determined by means of the laser velocimeter method. Water jets are characterized by three distinct regions, potential core region, transitional region and main region. The good agreement between the experimental and theoretical values of axial fluid pressure in a water jet is obtained under the condition that the transitional region is taken into account in the calculations.