1、IQ”. .*. -RESEARCH MEMORANDUIWEXPERIMENTAL INVESTIGATION OF THE EFFECTS OF SUPPORTINTERFERENCE ON THE PRESSURE DISTRIBUTION OF A BODYOF REVOLUTION AT A MACH NUMBER OF 3.12 ANDREYNOLDS NUMBERS FROM 2X106 TO 14x106By L. Eugene Baughman and John R. JackLewis Flight Propulsion LaboratoryCleveland, OhioN
2、ATIONAL ADVISORYFOR AERONAUTICSWASHINGTONAugust5,1953.- *m=. _k.b” i COMMITTEEProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TECH LIBRARY KAFB, NMlx NACA RM E53E28m NATIONAL ADVISORY COMMITTEE FOR AEROIUUTICSIillllllllllillllll!lllllllllulln0143402.
3、NISEARCH MEMORAIWXIMEXPERIMENTAL INVESTIGATION OF THE EFFECTS OF SUPPORT CEONAnTHE PRESSURE DISTRIBUTION OF A BODYNUM8ER OF 3.12 AND mwOrDs NUMBERSOF REVOLUTION AT A MACHFROM 2x106 TO 14x106By L. Eugene Baugbman and John R. JackSUMMARYexperimental investigationwas performed to determine theeffect on
4、 base and forebody pressures of using a sting modified withvarying length splitter plates and fins instead of a conventional stingto support a cone-cylinderbody of revolution. The investigation wasconducted at a Mach number of 3.12 for a Reynolds nuder range of 2X106to z4x106 and for an a,e of,attac
5、k range of 0 to 9.The influence of the varying length splitter plates and finmodifi-. cations was confined to local disturbances on the forebody and base.With the splitter plate there was a negligible effect on body pressuresand with the fin, a smalL effect on body pressures.aFor Reynolds numbers of
6、 8X106 and 14x106 there was a negligibleeffect of the splitter plate modification on the base pressure, and ata Reynolds number of 2x106 there was a small effect. Positioning theleading edge of the splitter plate at or ahead of the base made noareciable change in the influence of the modifications o
7、n base pres-sure at a Reynolds number of 14x106. With the fin-type modificationthere was a small increase in base pressure.Varying the angle of attack did not appreciably change the magni-tude of the interference of the suort modification.Provided by IHSNot for ResaleNo reproduction or networking pe
8、rmitted without license from IHS-,-,-NACA RM E53E28INTRODUCTIONIn wind tunnel testing it is essential that interference effectsbe minimized or accounted for in the presentation and use of data. Inthe investigationof sting-mountedbodies of revolution in a supersonicstream the effects on base pressure
9、 can be large, as is shown inreference 1. By keeping the sting diameter-smallrelative tcthe base-diameter the effect of the sting can be minimized, but with bodies ofrevolution that are severely boattailed the sting diameter may becometoo small to provide adequate support for the model.The purpose o
10、f this investigationat the NACA Lewis laboratory isto determine the effect on base and forebod pressures (with emphasison the former) of using a modified sting instead of a conventionalsting support. The pressure distributionswere experimentallydeter-mined for a body of revolutionwith both a convent
11、ional and a moti-?iedSti? at a Mach number of 3.12 and over a Remolds number range of2X1O to 14X106. Angle of attack range was from 0 to 9.- - SYM80LSThe following symbols.are used in this report: . -,pressure coefficient, p - Po/body lengthfree-stream Machstatic pressure.nuniber P- free-stresmdynsm
12、ic pressure, T/2poMo2Reynolds number, p UO 2/ufree-stream velocity . -x,r,e cylintiical coordinates .a angle of attackT ratio of specific heats, 1.40v viscosityP density-.-.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA RM E53E28 3. $ perturbat
13、ion velocity potential. Subscripts:o free-stream conditionsb baseAPPARATUS AND PRocmDuREThe tests were conducted in the NACA Lewis 1- by l-foot variableReynolds number tunnel, a nonreturn tunnel with test section Mach numberof 3.12&0.03. The inlet pressure varied from 7 to 50 pounds per squareinch a
14、bsolute and a stagnation temerature of 55*50 F was maintainedthroughout the investigation. In order to reduce condensation effects.41 to a negligible smount, the tunnel air was dried to a dewpoint of approx-0imately -55 F.$. A /“Q -.08 / .#2 - “* - “A 0“=35=-.06.-12 -8 -4 0 4 8 12- .-Angle of attack, a, deg(c) With finj 9, OO.Figure 8. - Concluded. Variation of bade pressure coefficient with angle ofattack for Reynolds numbers of 14K106, 8X106, and 2x106.NACA-LaJWIey -8-5-53- 4W.-.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
