Aerodynamic Characteristics of an Axisymmetric Body Undergoing a Uniform Pitching Motion

Smith, Lloyd H.; Nunn, Robert H.

doi:10.2514/3.57059

Cited by 30 publications

(7 citation statements)

References 6 publications

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“…As far as Ref. 13 is concerned, the low turbulence intensity (<0.2%) suggests that the results may be only mildly affected by unsteadiness.…”

Section: Comparison Of Prediction Methods With Experimental Resultsmentioning

confidence: 93%

“…Although there is a discrepancy of 10% between these maximum values of out-of-plane force, it would be advisable to await further experimental results before making adjustments to the prediction method, since the accuracy of the experimental method used in these tests was not high. The results of Smith and Nunn 13 were obtained on a model of overall length equal to \5D, including a 3D ogive nose. Three values of Reynolds number (based on body diameter) were used, namely 5xl0 4 , 8xl0 4 , and 1.4xl0 5 .…”

Section: Comparison Of Prediction Methods With Experimental Resultsmentioning

confidence: 99%

“…Details of freestream turbulence intensity are given in Ref. 13 while Ref. 1 quotes both turbulence intensity and scale.…”

Section: Comparison Of Prediction Methods With Experimental Resultsmentioning

confidence: 99%

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Prediction of aerodynamic out-of-plane forces on ogive-nosed circular cylinders

Lamont

Hunt

1977

Journal of Spacecraft and Rockets

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This paper describes an empirical method for predicting the aerodynamic out-of-plane forces and moments on circular cylindrical bodies with tangent-ogive noses. The method is derived from experimentally determined distributions of out-of-plane force over the cylindrical body. It is applicable to incompressible flow conditions and is based mainly on experimental results where the boundary layer over the body was laminar at separation. An examination of the available experimental data on overall out-of-plane forces and moments suggests that some of this data may have been affected by a form of unsteadiness which is determined by the test facility. The predictions of the present method show good agreement with the limited amount of experimental data which is considered to have general significance.ofD , ofF et c. Nomenclature = coefficient of out-of-plane force per unit length based on cross flow dynamic pressure and cylinder diameter = values of C of at points B, D and F, respectively, of the characteristic distribution (Fig. 1) = coefficient of overall out-of-plane force based on freestream dynamic pressure andirD 2 /4 -coefficient of overall out-of-plane moment based on freestream dynamic pressure and itD 3 14. = diameter of cylinder = nose fineness ratio ,L N /D = overall length of the model = length of the nose = quantities which determine the shape of the first half cycle, [Eq. (1)] = cylinder radius = Reynolds number , D csca U/ v = Reynolds number, DU/v =flow development time for an impulsively started cylinder = Vt/R for an impulsively started cylinder, x tana/R for an inclined cylinder = values of 1 at points A, B, etc. of the characteristic force distribution (Fig. 1)= freestream velocity for an inclined cylinder = freestream velocity for an impulsively started cylinder = axial distance from nose apex -angle of inclination to the freestream velocity = kinematic viscosity

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“…As far as Ref. 13 is concerned, the low turbulence intensity (<0.2%) suggests that the results may be only mildly affected by unsteadiness.…”

Section: Comparison Of Prediction Methods With Experimental Resultsmentioning

confidence: 93%

Section: Comparison Of Prediction Methods With Experimental Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Prediction of aerodynamic out-of-plane forces on ogive-nosed circular cylinders

Lamont

Hunt

1977

Journal of Spacecraft and Rockets

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“…21. As in the case of the effect of pitch rate measured by Smith 19 (Fig. 11), very modest moving wall velocity can cause a large discontinuous change of the aerodynamic loads.…”

Section: Work In Progress or Completed Very Recentlymentioning

confidence: 93%

“…Effect of pitch rate on the normal force of an ogive-cylinder in the critical Reynolds number region 19. ( |d) FORE-('/ d) AFT-ATTACHED TO AFTERBODY fThe quoted 6% oscillatory variation of the freestream speed19 may have been responsible for this early subcritical/supercritical transition.…”

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confidence: 99%

Steady and Unsteady Vortex-Induced Asymmetric Loads on Slender Vehicles

Ericsson¹,

Reding²

1981

Journal of Spacecraft and Rockets

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b c C m D d ' d d J I 1 L M M n N P N q Re R d S S t U x Y a a /3 7 Nomenclature wing span reference length , c = d f or bodies dC m /da;Ce f3 = dC e /d0 drag,coefficentC z> =Z)/(p 00 t/i/2)S sectional drag , coefficient c d = d ' I ( p «, U 2 , /2)c maximum diameter for body of revolution mean diameter, d=\ J 0 2 rd(x/£) bio wing momentum, coefficient body length forebody length forward of rotation center (Fig. 8) nose length = rolling moment, coefficient C, = £/ (p* U^ /2)Sb vortex wake wave length Mach number pitching moment, coefficient C m =M p /( Poo Ul/2)Sc yawing moment, coefficient C n =n/(p 00 U 2 00 /2)Sc = normal force, coefficient C N =N/ (p^ C/i/2)S = nose tip roll rate = pitch rate Reynolds number based on d max and freestream conditions; usually Re = R d Reynolds number, R d = U^d/vr eference area, S = ird 2 /4 reference area ( = projected wing area) time velocity axial body-fixed coordinate (distance from apex) side force, coefficient C Yangle rotation of plane of symmetry of forebody vortices (Fig. 8) cone half-angle 6 A = apex half-angle p = air density = roll angle <£' = coning angle (Fig. 8) 5 = three-dimensional separation angle (Fig. 15) a' = total angle of inclination (Fig. 8) v -kinematic viscosity oj = angular rate Subscripts A = apex AM = effective apex angle A V = asymmetric vortices c = cone n = normal to body axis TV =nose P = port side s = separated flow S = starboard SV = symmetric vortices UV = unsteady vortices v = vortex W =wall oo = freestream conditions Introduction T HE continually increasing performance demands on present day aircraft and missiles have brought on intensive research aimed at providing the needed understanding of the vehicle aerodynamics at high angles of attack where separated flow vortices often have a dominating influence. Recently there has been a series of papers reviewing the state of the art for the prediction of these high-a aerodynamics. M Nielsen 1 ' 2 concentrated his attention on the existing capability of predicting the missile aerodynamics at high angles of attack where the effects of symmetric vortices Lars E. Ericsson has published more than 100 papers in his related fields. Pete Reding, an Associate Fellow of AIAA, has had roughly 22 years experience in the aerospace industry working generally in the field of unsteady aerodynamics. He was first mystified by body vortex effects during his two-and-a-half years at what was then Douglas Aircraft Company, where he worked immediately after graduation from the University of Michigan in 1958. Now at Lockheed Missiles and Space Co., Inc. (since 1961) he has wrestled with separated flows, booster aeroelastic stability, airfoil stall, the dynamics of bulbous based bodies, ablating bodies, shuttle vehicles, decelerators, dynamic support interference, and aeroacoustics. Not one to give up easily he has once again attacked the mysteries of body vortices. 98 L.E. ERICSSON AND J.P. REDING J. SPACECRAFTfrom the forebody and its canard surfaces on aft body and fins have demanded major new analytical/ex...

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