Interaction of a Turbulent-jet Noise Source with Transverse Modes in a Rectangular DuctNational Aeronautics and Space Administration, Scientific and Technical Information Office, 1978 - Acoustic models - 39 pages |
Common terms and phrases
15-centimeter 25-kilohertz range 5-kilohertz acoustic response acoustic spectra amplitude AN/Ako anemometer asymmetric pressure spikes asymmetric singularities pressure butterfly valve cutoff mode dB referenced decay decibels detected diameter orifice downstream duct axis duct coordinate duct cross section duct modes duct response duct walls Effects of Microphone eigenfrequencies Elapsed equation excitation experiments flow-duct free space frequency range higher order modes increases Institute of Technology kilohertz Lewis Research Center long tube Low-frequency spectra Mach number mass flow rate Massachusetts Institute measured Microphone location mode cutoff frequency mode shape NASA number of modes number of propagating Orifice diameter orifice plate oscillation pipe pressure response pressure spectrum propagating modes quency radiation radiative resistance range of jet rectangular duct referenced to 2x10-5 Screech peaks shown in figure singularities pressure spikes Sound pressure level source in free spectrum analyzer test section TRANSVERSE MODES transverse wave turbulent jet upstream