NASA NACA-RM-A54J19-1955 Application of wing-body theory to drag reduction at low supersonic speeds《在低超声速时 翼身原理对减阻的应用》.pdf
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1、RESEARCH MEMORANDUM APPLICATION OF WING-BODY TIIEORY TO DRAG REDUCTION AT LOW SUPERSONIC SPEEDS By Barrett S. Baldwin, Jr., and Robert R. Dickey Ames Aeronautical Laboratory Moffett Field, Calif. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACARM
2、A-9 AEF!LICATION OF WING-BODY THEDRY TO IXRAG RELOWXCON AT mw SUPERSONIC SF= By Barrett S. Baldwin, Jr., and Robert R. Dickey J=-=Y 28, 1955 Page 10, lines ll and 14: Replace the expression f - . t NhCA-,-LangIey - S-4-65 - ZOO Provided by IHSNot for ResaleNo reproduction or networking permitted wit
3、hout license from IHS-,-,-c NACARM A54Jl.g i; -5 NATIONAL ADVISORY C however, ft was pointed out that, at higher supersonic Mach numbers, this modlffcation would sometfmes result in drags greater than that of the original config- uration. In reference 1 a method for contouring the fuselage of a wing
4、- b- Consider a wing-body cabination such as shown in sketch (a). Let x be the coordinate in the free-stream direction, y the spanwise coordi- nate, and z the remain- z ing Csztesisn coordinate HX in the thickss dfrec- tion, with the origin at the center of the body. AMachplane can be defined as a p
5、lane with its normal at 811 angle of tan-1(1/p) to the x axis. Let (xl,p,cp) denote the Mach plane which inter- sects the x axis at x and has the projection of its normal on the yz plane at an angle cp to the y axis. Let r* - S(x,fl,Q) be the area of the projection on the yz Sketch (a rt plane of th
6、e cross-eectfonal area intercepted on the configuration by the Mach plane (x,S,q). Then the drag of the configuration is the average with respect to cp of the drags of the equivalent bodies of revolution defined by the area distributfons S(x*,B,q). A method introduced in reference 4 is used in refer
7、ence 1 to evaluate the drag of each equivalent body of revolution. The variable 13 is defined by the relation X = k cos e 2 (1) where B is the length of the equivalent body. Then a set of quantities An(P,cp) are defined a8 the coefficients of sin n0 in a Fourier series expansion of Consequently the
8、An(l3,q) csn be determined from the relation An(P,cP) = $ s o as(x, ati(r -I ax* (2) Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4 NACAHMA54Jlg Finally, the drag -of the configuration is given by (3) ” n=i Within the framework of the linear theor
9、y this result is valid only for equivalent bodies of revolution with no diecontinuities fn the gradienti of the area distributions. It should be noted that unless all parts of the configuration lie between the nose Mach cone and the forward Mach cone from the tafl, the equivalent body length, 2, wil
10、l be greater than the actual body length in scme cases. However, by consideration of streamwise body extensions of venishingly Bmall cross-sectional area, it can be seen that a constant value of 2 equal to or greater than the length of the longest equivalent body can be used In equation (1). Series-
11、expansion method.- In this section the Fourier series coef- ficfents defined in equation (2) till each be expanded in a finite series so that the drag formula can be expressed as a power series in powers of P* This manipulation leada convenient set of geometric plane method. to an expression of the
12、drag Fn terms of a parameters which were not apparent in theMach By the use of equation (l), equation (2) can be written as s z/2 as(x,p,ql) sinbe) at -z/2 ax sin 8 or after a partial integration * * i . + l .L .- - (4) provided that astxt, B,) ax* and S(x*,g,cp) are zero at the nose and t J;: c;i;:
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