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CEAS Aeronautical Journal

, Volume 4, Issue 2, pp 123–138 | Cite as

Wind-tunnel studies on maneuvering slender bodies

  • O. WysockiEmail author
  • E. Schülein
  • H. Rosemann
Original Paper

Abstract

In this paper, the first experimental results of tests with a new model support designed for simulations of high frequency and high amplitude pitching maneuvers are presented. A generic missile model with a blunt nose was used for which static test data from earlier experiments with a conventional model support were existing. At the beginning, static tests were done for comparison purposes to judge the influence of the new setup (model support, sting for the model, pivot arm) on the measured forces and moments. Afterwards, dynamic tests with sine oscillations at frequencies of \(f_{\rm a}=0.05\ldots 4\,\hbox{Hz}\) and angles of attack varying between \(\alpha = 0^{\circ} \ldots 45^{\circ}\) were performed. Beside the qualification of this new test rig, the tests were used to study the “Phantom Yaw Effect” and to prove an interactive method of its control. This phenomenon is characterized by unwanted yawing moments resulting from asymmetric vortices which can occur on slender bodies at high angles of attack. In the tests, a lee-vortex control device with symmetrically arranged longitudinal slot nozzles producing “air-jet strakes” was demonstrated to decrease the yawing moments both under static and dynamic conditions.

Keywords

Phantom Yaw Maneuver simulation Asymmetric vortices Slender bodies Flow control Experiments 

List of symbols

Greek symbols

α

Angle of attack

\(\Updelta\alpha\)

Pitching amplitude

\(\alpha_{\rm AV}\)

Onset angle asymmetric vortices

\(\alpha_{\rm SV}\)

Onset angle symmetric vortices

\(\alpha_{\rm UV}\)

Onset angle unsteady vortices

\(\alpha_{\rm N}\)

Effective angle of attack at model’s nose

δ

Offset angle of x-axis and radius to pivot for a POI

ω

Angular velocity

\(\dot{\omega}\)

Angular acceleration

σ

Standard deviation

Roman symbols

a

Acceleration

\(c_x, c_y, c_z\)

Aerodynamic force coefficients

\(c_l, c_m, c_n\)

Aerodynamic moment coefficients

\(c_{x,{\rm {bp}}}\)

Axial force coefficient at model base

D

Model diameter

\(F_x, F_y, F_z\)

Force in X-, Y- or Z-direction

\(F_{\rm act}\)

Actuation force of hydraulic system

\(f_{\rm a}\)

Actuation frequency

\(f_{\rm s}\)

Sampling frequency

J

Moment of inertia

L

Model length

M

Mach number

\(M_x, M_y, M_z\)

Moment around X-, Y- or Z-axis

m

Model mass

\(q_\infty\)

Free stream dynamic pressure

\(p_\infty\)

Free stream static pressure

\(p_0\)

Stagnation pressure

\( p_{\rm B}\)

Base pressure

\(Re_D\)

Reynolds number (based on model diameter)

r

Distance to the pivotal point

t

Time

\(t_{\rm m}\)

Measurement time

\(\Updelta x\)

Distance between 2 points on x-axis

\(\Updelta z_0\)

Distance wind tunnel wall to main body axis

Abbreviations

AoA

Angle(s) of attack

BRP

Balance reference point

CAD

Computer-aided design

CG

Center of gravity

DLR

German Aerospace Center

MCS

Model coordinate system

MEMS

Microelectromechanical systems

POI

Point of interest

RCS

Rotation coordinate system

RMS

Root mean square

RP

Reference point

RS

Reference (coordinate) system

TWG

Transonic wind tunnel Göttingen

Subscripts

x

X-direction of corresponding coordinate system

y

Y-direction of corresponding coordinate system

z

Z-direction of corresponding coordinate system

M

Model (coordinate system)

N

Model nose

CG

Center of gravity

Acc

Accelerometer parameter

in

Inertial

BRP

Referring to balance reference point

bpc

Base pressure corrected

References

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Copyright information

© Deutsches Zentrum für Luft- und Raumfahrt e.V. 2013

Authors and Affiliations

  1. 1.German Aerospace Center (DLR), Institute of Aerodynamics and Flow Technology (AS)GöttingenGermany

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