Numerical simulation of non-stationary flows in water jet cutting

This work was supported by The Ministry of Education, Youth and Sports from the Large Infrastructures for Research, Experimental Development and Innovations project IT4Innovations National Supercomputing Center – LM2015070.The use of a high-speed water jet is one of the modern technologies for cutting and machining the material. High efficiency can be achieved by either by increasing the operating pressure or by using a non-stationary mode created by an ultrasonic generator. The use of ultra-high pressures in continuous mode induces extreme loading to high pressure parts of the cutting machine. The alternative approach using pulsating jets from an ultrasonic generator can increase the efficiency of the cutting without the need of such high water pressures. The impact of droplets of the pulsating jet generates much higher impact pressure than the stagnation pressure generated by the action of continuous jet. The efficiency of the cutting is further increased by cyclic loading of the target as well as by large shear stresses generated by the jet