In order to predict the multiple jets screech phenomenon in the scarfing process of rolling slab,a three-dimensional transient mathematical model has been developed to investigate the turbulent multiple jets merging.Large eddy simulation(LES)with dynamic Smagorinsky sub-grid scale(SGS)approach was applied to simulate the turbulent multi-jet flow field.The acoustic field was calculated by the Ffowcs Williams-Hawkings(FW-H)integral equation.In consideration of the compressibility of high Mach number gas jets,density-based explicit formulation was adopted to solve the coupled system of governing equations,and the viscosity was approximated by Sutherland kinetic theory.The multiple jets merging acoustic characteristic was demonstrated,as well as the noise intensity were predicted with a good accuracy of practical data.The results indicated that multiple jets merging phenomenon is induced by the Coanda effect,and adding to the complexity and instability of flow field.The main factors affecting multiple jets merging are injection orifice diameter and distances between orifices.The overall sound pressure level(OASPL)profiles have a directive property,which is also influenced by the multiple jets merging.Controlling multiple jets turbulent intensity and taking advantage of the noise directionality are both good measures for noise reduction.The conclusion obtained in this study can provide valuable data to guide the development of manufacturing-green technology in the scarfing process.