By A.S. Ginevsky, Y.V. Vlasov, R.K. Karavosov
Results of experimental study on aerodynamic and acoustic regulate of subsonic turbulent jets by means of acoustic excitation are awarded. It used to be tested that those regulate tools, originated by way of authors, not just can accentuate blending (by acoustic irradiation at low frequency), but in addition particularly ease it (at high-frequency irradiation). This learn monograph provides the up to date result of the authors supplemented via different investigations performed in united states, Germany and nice Britain. The equipment for the numerical simulation of subsonic turbulent jets less than acoustic excitation are defined intimately, and examples are reviewed of useful purposes, together with relief of turbojet engine noise and acoustic regulate of self-sustained oscillations in wind tunnels.
Read Online or Download Acoustic Control of Turbulent Jets PDF
Best aerospace books
William Wolf brings his meticulous study to explain the little identified Douglas B-18 Bolo which was once America's such a lot various entrance line bomber on the time of Pearl Harbor. through the years the tale of the airliner became bomber has languished in obscurity and the few articles at the topic in renowned aviation magazines have emphasised its faults and maligned it as the cheap bomber that had few virtues.
X Planes of the 3rd Reich sequence - An Illustrated sequence on Germanys Experimental airplane of worldwide conflict II. The pilot-operated Bachem Ba 349 Natter (Adder) was once among the unforeseen new guns Germany was once trying to ideal for a greater safety opposed to Allied heavy bombers. the belief of the ground-to-air missile to decelerate, if no longer cease, attacking airplane used to be one of many maximum advancements to return out of global warfare II, and Germany led the sphere.
Extra info for Acoustic Control of Turbulent Jets
70] for the case of transverse acoustical excitation of a turbulent jet. Fig. 5 for different levels of the sound pressure, L, for two issue speeds U o = 10 and 20 mls. Here the following facts engage our attention. First, these functions are defined for strict1y fixed levels of the sound pressure near the nozzle edge and for v; I U o respectively. Thus the curves ulu_ = 1)7\ (St,) and u' lu~ = 1)72 (St s ) are smooth unlike the similar curves in the previous paragraph. : 10). The action sign change in Fig.
15) at the section xl Bo = 200 where the suppression tumed out to be maximum. 2. 017 corresponding to the maximum spatial increase of disturbances in complete agreement with the linear theory of stability. 022. 025 the values u' / u~ > 1 can be achieved. 4 .. 8 Fig. 13. l) L = 105 dE, 2) L = 135 dB, 3) L = 135 dE. 46 CHAPTER 2. 1 ,----------------------------------, • 1 .. L-_ _ _ _----' 1 2 4 6 8 x/d Fig. 14. Change of u / u_ a10ng the jet axis for Uo = 10 mls, St s =9 1) L = 105 dB, 2) L = 135 dB.
54]. 1. 1 y/ro Fig. 6. 89. 5) is attended (Fig. 25]. As follows from Fig. 53]. 23]. g. s0o / U o for x / d = 4 where 0 is the momentum loss thickness at the initial section of a laminar boundary layer (Fig. 10 for a jet under longitudinal acoustical excitation. 022 . ° 40 CHAPTER 2. 5 2 5 St Fig. 7. 4. 1 x/d Fig. 8. 5. 1. 5 O 500 1000 t. ls Fig. 9. Change in the Euler time correlation of the longitudinal velocity pulsations at the points x! d = 3, Y / d = O and x! 75 , 3) a radiation-free jet. 017 .