1、TECHNICAL NOTE 2972THEORETICAL PRESSURE DISTRIBUTIONS AND WAVE DMGSFOR CONICAL BOATTAILSBy John R. JackLewis Flight Propulsion LaboratoryCleveland, OhioWashingtonJuly 1953. . . . . ,- . . - .- -. . . . . . . .- -Provided by IHSNot for ResaleNo reproduction or networking permitted without license fro
2、m IHS-,-,-TECHUBRARY tC/WB, NMlM16MlMlllollllln1s13CIL5952maw fmmom COMMITIEEF MROIWUZ!ICSTKXKKML NOTE 2972TEIEOREIIICALPRESSURE DISZKIBUITONS AND MNll IWWSFoR CONICALBomTAm3By John R. JackAfterbody pressure distributions and wave drags were calculatedusing a second-ordertheory for a variety of coni
3、calboattails at zerosugle of attack. Results are presented for Mch numbers from 1.5 to4.5, area ratios from 0.200 to 0.800, and boattail angles from 3 to II”.The results indicatethat for a given boattail angle, the wave dragdecreaseswith increasingMach nuriberd area ratio. The wave drag,for a consta
4、nt srea ratio, increaseswith increasingboattail angle.For a specificlhowever, the area ratios of practical interest correspondto boattai.1.lengths which, in general, are within this Mmitat ion. !l?heprocedure presented in reference 3 proves to be an expedientmeans ofobtatiingboth a first- and a seco
5、nd-ordersolution. The average timefor calculatingthe combined first- and second-ordersolutionswasapprccdmately 11 cmput er hours. .Wave-tig coefficientsfor each boattail were obtainedby graph-ically integratingthe pressure distributio over the boattail surfaces.The wave-drag coefficientwas based on
6、the maximum area of the boattailand is deftiedbywhere Cp is the exact isentropicpressure coefficient,r is the localboattail radius, and and R are the maxhum and minimum boattailradii, respectively.I?XSQECSAND DEXUSSIONPressure distributionsand wave drags. - The variations of pressurecoefficient in t
7、he axial direction for the conicalboattaiM me pre-sented in figure 1 for selectedvalues of boattail angle and free-stresmProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.cNACA TN 2972while the secant-parabolicboattail area ratio, 0.200.NACA-hq -7-6-53- 1004z. . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
