Injecting water in the mixing layer of high velocity jets is a means to reduce their acoustical radiation. In order to evaluate the efficiency of this method in the case of highly heated supersonic jets, the C.N.E.S. has built a new experimental facility (MARTEL). It provides supersonic flows with jet Mach number up to 2.9 and stagnation temperature up to 2200 K. Depending on the injection configuration, significant reductions of the far-field acoustical intensity can be obtained (up to 7 dB for certain observation angles). However, these reductions are less important than those obtained in the case of cold supersonic jets. Aeroacoustical characteristics of these flows are responsible of these differences. We present in this study the effect of water injection on the different components of supersonic jet noise, mainly on shock associated noise and Mach wave radiation.
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