A comparison between the SR-6 propeller noise in flight and in a wind tunnel

Abstract

High-speed turboprops offer an attractive candidate for future aircraft because of their high propulsive efficiency. However, one of the possible problems associated with these propellers is a high level at cruise that might create a cabin environment problem for future aircraft powered by these propellers. Models of these propellers have been tested for acoustics in the Lewis 8-by-6-ft wind tunnel and on the Dryden JetStar airplane. This paper shows comparisons between the airplane and wind tunnel data for the SR-6 propeller. The comparison of the maximum blade passing tone variation with helical tip Mach number taken in flight with that taken in the tunnel showed good agreement when corrected to the same test conditions. Directivity comparisons also showed fairly good agreement. These good comparisons indicate that the wind tunnel is a viable location for measuring the blade passage tone of these propellers.

Prediction of propfan noise by a frequency-domain scheme

“…(5)] and theoretical and wind-tunnel results published by NASA. 16 Both U.S. and ONER A calculations (the first one in the time domain, the second one in the frequency domain) give similar variations of the sound level at the blade passing frequency as a function of the helical tip Mach number. For values lower than 1.1, experimental levels lie within the two types of computations.…”

Summary and recent results from the NASA advanced high-speed propeller research program

“…31, 320 and 33) was used to predict the noise of the 8-bladed 45° swept propeller model (SR-3) and the results are reported in ref. 34 This model predicts the noise resulting from the shock pressure rise caused by the propeller tip alone. The shock pressure rise prediction for the 8-bladed 45° swept propeller is compared to the data in figure 23.…”

Computational Aeroacoustic Prediction of Propeller Noise Using Grid-Based and Grid-Free CFD Methods

“…For model validation and propeller design, a number of experiments have been performed and published as presented in Table 1 [18] 1933 800 0.0 Free Field* Hicks and Hubbard [19] 1947 1100-4800 0.0 Free Field* Hubbard [20] 1950 2300-3800 0.0 Free Field* Hubbard [21] 1952 3900-6900 0.0 Free Field* Karbjun [22] 1955 1675 0.0 Free Field* Karbjun [ [36] 1986 7200-11400 0.1 Wind Tunnel Dobrzynski et al [11] 1986 1069-2800 0.1-0.2 Wind Tunnel Woodward et al [37] 1987 5600-8800 0.2 Wind Tunnel Dittmar and Stang [38] 1988 5600-10100 0.6-0.85 Wind Tunnel Schulten [39] 1988 N/A N/A Wind Tunnel Dittmar [15] 1989 5100-9500 0.6-0. [25] 1978 SR-2, SR-1M*, SR-3* 0.622 Dittmar et al [26] 1980 SR-2, SR-1M*, SR-3* 0.622 Dittmar and Jeracki [27] 1981 SR-3* 0.622 Dittmar and Jeracki [28] 1981 SR-3* 0.622 Dittmar and Lasagna [29] 1981 SR-3* 0.622 Dittmar et al [30] 1982 SR-6* 10 0.696 Succi et al [31] 1982 1C160 0.473 Sulc et al [32] 1982 NACA 0016 2.5 Dittmar et al [33] 1983 SR-6* 10 0.696 Dittmar and Lasagna [34] [38] 1988 SR-7A* 0.622 Schulten [39] 1988 N/A 0.732 Dittmar [15] 1989 SR-2 0.622 Dittmar and Hall [40] 1990 SR-7A* 0.622 Soderman and Horne [12] 1990 SR-2 0.591 Zandbergen et al [41] 1990 Fokker 50 (ARA-D) 0.732 Dittmar et al [42] 1991 SR-7A* 0.622 Schulten [43] 1997 LSP, HSP* 0.9…”