Scaling Laws and a Method for Identifying Components of Jet Noise

摘要: It is well established that there are three principal jet noise components for imperfectly expanded supersonic jets. However, to this date has been no reliable and practical method identifying the individual components. First, new scaling laws turbulent mixing component developed from a comprehensive experimental database generated by author. The based on explicit recognition a) variation of overall sound power level with velocity weak dependence stagnation temperature ratio; b) pressure at every radiation angle function ratio. Therefore, behavior each can be characterized two independent parameters: ratio These findings set study apart past approaches form basis methodology here. demonstrated clearly excellent collapse spectra over entire frequency range. Once normalized or master established, it trivial matter subtract these total measured obtain shock-associated noise. For moderately heated jets, same spectral as noise, wide range higher frequencies. At lower angles in forward quadrant, substantial decrease values exponents increased. Proceeding aft, start rise peak sector radiation, exponent becomes less sensitive unlike angles, stays close unheated jet.