NASA-TN-D-5392-1969 Experimental pressure distributions for a family of blunt bodies at Mach numbers from 2 49 to 4 63 and angles of attack from 0 degrees to 15 degrees《当马赫数为2 49至4.pdf
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1、EXPERIMENTA PRESSURE DISTRIBUTIONS FOR A FAMILY OF BLUNT BODIES AT MACH NUMBERS FROM 2.49 TO 4.63 AND ANGLES OF ATTACK FROM Oo TO 15 5 by Robert L. Stullings, Jr., und Dorothy T. Howell Lungler Reseurch Center Langley Stution, Hampton, Vu. NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, D.
2、 C. AUGUST 1969 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TECH LIBRARY KAFB, NM 19. Security Classif. (of this repart) Unclassified 2. Government Accession No. I 1. Report No. NASA TN D-5392 EXPERIMENTAL PRESSURE DISTRIBUTIONS FOR A FAMILY OF B
3、LUNT BODIES AT MACH NUMBERS FROM 2.49 TO 4.63 AND ANGLES OF ATTACK FROM Oo TO 15 Robert L. Stallings, Jr., and Dorothy T. Howell 4. Title and Subtitle 7. Author(s) XI. Security Classif. (of this page) 21. No. of Pages 22. Price* Unclassified 85 $3.00 9. Performing Organization Name and Address NASA
4、Langley Research Center Hampton, Va. 23365 12. Sponsoring Agency Nome and Address National Aeronautics and Space Administration 3. Recipients Catalog No. 5. Report Date Auoust 1969 6. Performing Organization Code 8. Performing Orgoniration Report N L-6667 IO. Work Unit No. 124-07-17-02-23 _ 11. Cont
5、ract or Grant No. 13. Type of Report and Period Cover 0. The measured pres- a! 0. For these locations, the In general, the effect of angle of attack on the measured pressure distributions shown in figure 4 is as would be expected. This effect with increasing angle of attack consists of an increase i
6、n the magnitudes of the pressures on the windward side of the model ( = 180O) and a corresponding decrease on the leeward side ($ = Oo). The results shown in figure 4 at a= 15 are replotted in figure 5 to show more clearly the effect of model geometry on the pressure distributions. These results are
7、 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-presented with shoulder radius as the varying parameter for a constant value of nose radius. The model geometry symbol notation corresponds to the same values of rc/d for all parts of figure 5. extra
8、polations extending from the subsonic pressure measurements at the last instrumen- tation station to a pressure corresponding to sonic velocity at s/s2 = 1. For each value of rn/d the pressure distributions for all values of rc/d are bounded by the pressure distributions obtained on the hemispherica
9、l model (rc/d = 0.5) and the spherical cap model (rc/d = 0). With decreasing values of rn/d, the pressure distribution of the spherical cap models approach those of the hemispherical model, and thus the overall extent of the corner-radius effect is reduced. This trend is more apparent on the leeward
10、 side of the models ( = Oo) than on the windward side ( = 180O). The dashed curves shown for these models with rc/d = 0 are The effect of Mach number on the pressure distributions of selected models repre- senting the full range of geometrical variables is shown in figure 6 for an angle of attack of
11、 Oo. The local measured pressures have been normalized by the measured value at s/d = 0 for two reasons: (1) to make them directly comparable with normalized pressurc distributions for M, = 10 from reference 2 and (2) to eliminate errors associated with using a computed value of (Pt,2), which is sig
12、nificantly affected by the possible Mach number variations discussed previously. A comparison of the pressure distributions for the Mach number range shown in figure 6 clearly indicates that the Mach number effect at a! = 0 rapidly diminishes with increasing nose bluntness (decreasing rc/d) and Mach
13、 number. The pressure distributions of the present investigation at M = 4.63 are approximately the same as those shown for M, = 10 from reference 2. The effect of Mach number on pressure distributions for a!= 15 is shown in a 0 because of the limited instrumentation at this COI figure 7 for the Mach
14、 number range of this investigation. A pitot pressure was not measured on most models for dition. In order to minimize the errors associated with using a computed value of p as discussed in the preceding paragraph, the ratio pL/pt,2 was multiplied by the ratio (pt, 2/p,ax)cu,00; the latter ratio eff
15、ectively accounts for longitudinal Mach number gra- dient in the tunnel. In general, increasing Mach number results in a decrease in the magnitude of the pressure distributions; this trend is the same as that shown for a= 0. As would be expected, the Mach number effects on the pressure distributions
16、 of the hemispherical model relative to the respective stagnation points are very similar to the results shown at a!= 0 relative to s/d = 0. For the remaining models, the extent of the Mach number effect is different for the windward and leeward sides. On the windwarc side of the models, the Mach nu
17、mber effect decreases very rapidly with decreasing shoul- der radius for all values of rn/d. This same trend is shown on the leeward sides for ward surface is relatively insensitive to shoulder radius. The pressure distributions t, 2 I I Y rn/d = 00 and 1.933. For smaller values of rn/d, the Mach nu
18、mber effect on the lee- 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-shown for M, = 4.63 of this investigation for a! Oo are believed also to be applicable at higher Mach number flow for the following reasons: effect as shown in figure 7 occurs
19、for the hemispherical model and (2) the pressure dis- tributions on the hemispherical model at a! Oo are very similar to results obtained at CY= 0 as discussed previously. The pressure distributions at a!= Oo are essentially the same as the pressure distribution obtained at M, = 10 (ref. 2). (1) the
20、 maximum Mach number Circumferential Pressure Distributions Circumferential pressure distributions are shown in figure 8 for a selected num- ber of models representing the range of geometrical variables at a location 3 inches (76.2 mm) from the geometric stagnation point and at an angle of attack of
21、 15. Results were not obtained for model 1 at this location for a! 0. Analytical distributions are also shown in figure 8 from the following empirical equation based on the experimental data: pz w - L Pl L (0.072 cos2 - 0.5 cos + 0.428) + A pz L - pt, 2 = ( pt,2 4,2) Pt, 2 where p l,w and plYL are t
22、he measured windward ( = 180) and leeward ( = Oo) pressures, respectively, at a given value of s/d. The analytical distributions are in excellent agreement with the experimental data for the complete range of geometrical variables shown. The analytical distributions are also in excellent agreement w
23、ith the measured distributions for the test range of angle of attack as shown in figure 9 and for the test range of Mach number as shown in figure 10. SUMMARY OF RESULTS Pressure distributions were experimentally determined for a family of blunt bodies at Mach numbers from 2.49 to 4.63 and angles of
24、 attack from 0 to 15. The family con- sisted of bodies of revolution having variable nose and shoulder radii and cylindrical afterbodies 7.5 inches (191 mm) in diameter. The model geometry ranged from a hemi- sphere cylinder to a flat-face cylinder. The results are summarized as follows: 1. At an an
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