The Flow and Interference Effects of a Body of Revolution and Its Stabilizing Surfaces When at a Small Angle of Attack

1965 ◽  
Vol 87 (4) ◽  
pp. 941-952
Author(s):  
E. J. Rodgers
Keyword(s):  
Velocity Field ◽  
Angle Of Attack ◽  
Surface Flow ◽  
The Body ◽  
Body Of Revolution ◽  
Interference Effects ◽  
Measured Velocity ◽  
Pressure Distributions ◽  
Flow Effects ◽  
Real Flow

The flow over a body of revolution and its stabilizing surfaces, at an angle of attack, was studied experimentally in order to obtain a better understanding of the real-flow effects as well as the interference effects between components of the configuration. The velocity field about the configuration, the surface flow, and the pressure distribution were obtained with the model mounted in the wind tunnel of the Ordnance Research Laboratory. Analysis of the data showed there is an increase in lift on the body and a decrease in lift on the stabilizing surfaces from that of the isolated components at the same incidence to the flow. The interference effects between components is evidenced by the surface flows and pressure distributions as well as the vorticity distribution calulated from the measured velocity field. The decreased lift on the stabilizing surfaces is clearly related to the flow over the after part of the body.

Vorticity Generation of a Body of Revolution at an Angle of Attack

1964 ◽  
Vol 86 (4) ◽  
pp. 845-850 ◽  
Author(s):  
E. J. Rodgers
Keyword(s):  
Velocity Field ◽  
Body Surface ◽  
Angle Of Attack ◽  
Surface Flow ◽  
The Body ◽  
Distribution Data ◽  
Body Of Revolution ◽  
Vorticity Distribution ◽  
Vorticity Generation ◽  
Real Flow

An experimentally obtained velocity field about a body of revolution at a small angle of attack, and at subsonic velocity, is used to determine the vorticity distribution about the body. Surface-flow visualization and pressure-distribution tests are used to supplement the vorticity-distribution data in attempting to explain the mechanisms of the flow, and thus the differences between the real flow and that predicted by potential theory.

Measurements of turbulent crossflow separation created by a curved body of revolution

2007 ◽  
Vol 589 ◽  
pp. 353-374 ◽  
Author(s):  
P. A. GREGORY ◽  
P. N. JOUBERT ◽  
M. S. CHONG
Keyword(s):  
Flow Visualization ◽  
Skin Friction ◽  
Cross Sections ◽  
Separated Flow ◽  
Surface Flow ◽  
The Body ◽  
Body Of Revolution ◽  
Outer Flow ◽  
Friction Measurements ◽  
Surface Flow Visualization

Using the method pioneered by Gurzhienko (1934), the crossflow separation produced by a body of revolution in a steady turn is examined using a stationary deformed body placed in a wind tunnel. The body of revolution was deformed about a radius equal to three times the body's length. Surface pressure and skin-friction measurements revealed regions of separated flow occurring over the rear of the model. Extensive surface flow visualization showed the presence of separated flow bounded by a separation and reattachment line. This region of separated flow began just beyond the midpoint of the length of the body, which was consistent with the skin-friction data. Extensive turbulence measurements were performed at four cross-sections through the wake including two stations located beyond the length of the model. These measurements revealed the location of the off-body vortex, the levels of turbulent kinetic energy within the shear layer producing the off-body vorticity and the large values of 〈uw〉 stress within the wake. Velocity spectra measurements taken at several points in the wake show evidence of the inertial sublayer. Finally, surface flow topologies and outer-flow topologies are suggested based on the results of the surface flow visualization.

Prediction of Sheet Cavitation on a Rudder Subject to Propeller Flow

2007 ◽  
Vol 51 (01) ◽  
pp. 65-75
Author(s):  
Spyros A. Kinnas ◽  
Hanseong Lee ◽  
Hua Gu ◽  
Shreenaath Natarajan
Keyword(s):  
Velocity Field ◽  
Three Dimensional ◽  
Leading Edge ◽  
Slip Boundary Condition ◽  
The Body ◽  
Solid Boundary ◽  
Blade Surface ◽  
Lattice Method ◽  
Sheet Cavitation ◽  
Pressure Distributions

This paper presents two numerical methods, a vortex lattice method (MPUF-3A) coupled with a finite volume method (GBFLOW-3D) and a boundary element method (PROPCAV), which are applied to predict time-averaged sheet cavitation on rudders, including the effects of the propeller as well as of the tunnel walls. The coupled MPUF-3A and GBFLOW-3D determines the velocity field due to the propeller within the fluid domain bounded by tunnel walls. MPUF-3A solves the potential flow around the propeller by distributing the line vortices and sources on the blade mean camber surface and determines the pressure distributions on the blade surface. GBFLOW-3D solves Euler equations with the body force terms converted from the pressure distributions on the blade surface and determines the total velocity field inside the fluid domain. The tunnel walls are treated as a solid boundary by applying the slip boundary condition, and the propeller blades are modeled via body forces. The two methods are solved iteratively until the forces on the blade converge. The cavity prediction on the rudder is accomplished via PROPCAV, which can handle back and face leading edge or mid-chord cavitation, in the presence of the three-dimensional flow field determined by the coupled MPUF-3A and GBFLOW-3D. The present method is validated by comparing the cavity shapes and the cavity envelope with those observed and measured in experiment and computed by another method.

scholarly journals Preliminary Study on Aerodynamic Control of High-Angle-of-Attack Slender Body Using Blowing from Penetrating Flow Channels

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Ayane Sato ◽  
Hiroyuki Nishida ◽  
Satoshi Nonaka
Keyword(s):  
Angle Of Attack ◽  
Surface Flow ◽  
The Body ◽  
Slender Body ◽  
High Angle ◽  
Control Effect ◽  
High Angle Of Attack ◽  
Separation Line ◽  
Flow Channels ◽  
Aerodynamic Control

The objective of this study is to experimentally verify a new aerodynamic control concept of a high-angle-of-attack slender body. In the concept, penetrating flow channels are installed to the apex of the slender body. The blowing or suction is generated at the channel exits in response to the surface pressure distribution. First, the effects of the flow channels on the aerodynamic characteristics are experimentally investigated in a low-speed wind tunnel. The result shows the Suction-Blowing type channel is the most effective because its control effect does not reduce even in higher mainstream flow velocity. The peak value of the side force and yawing moment can be reduced by up to 64% and 49%, respectively. In addition, visualization of the surface flow pattern by the oil flow method shows that the Suction-Blowing type channel makes not only the primary separation line on the body side but also the secondary separation line on the body back become symmetric.

Incompressible potential flow past ‘not-so-slender’ bodies of revolution at an angle of attack

1975 ◽  
Vol 70 (4) ◽  
pp. 651-661 ◽  
Author(s):  
P. Sivakrishna Prasad ◽  
N. R. Subramanian
Keyword(s):  
Velocity Potential ◽  
Angle Of Attack ◽  
The Body ◽  
Virtual Mass ◽  
Bodies Of Revolution ◽  
Exact Theory ◽  
Pressure Distributions ◽  
Ellipsoid Of Revolution ◽  
Slender Bodies ◽  
Good Agreement

Using the method of matched asymptotic expansions, an expansion of the velocity potential for steady incompressible flow has been obtained to order ε4for slender bodies of revolution at an angle of attack by representing the potential due to the body as a superposition of potentials of sources and doublets distributed along a segment of the axis inside the body excluding an interval near each end of the body. Also, expansions of the coefficients of longitudinal virtual mass and lateral virtual mass have been found. The pressure distributions over an ellipsoid of revolution of thickness ratio ε = 0·3 at zero angle of attack and at an angle of attack of 3° obtained by the present method are compared with results obtained from the exact theory and that of Van Dyke. The virtual-mass coefficients are also compared with those obtained from the exact theory and are found to be in good agreement up to ε = 0·3.

The Mean Flow Structure on the Symmetry Plane of a Turbulent Junction Vortex

1990 ◽  
Vol 112 (1) ◽  
pp. 16-22 ◽  
Author(s):  
F. J. Pierce ◽  
I. K. Tree
Keyword(s):  
Velocity Field ◽  
Vortex Structure ◽  
Symmetry Plane ◽  
Leading Edge ◽  
Surface Flow ◽  
The Body ◽  
Mean Flow ◽  
Velocity Measurements ◽  
Vortex System ◽  
The Mean

The mean flow structure on the symmetry plane of a turbulent junction vortex is documented. A two-channel, two-color LDV system allowed nonintrusive measurements of the two velocity components on the symmetry plane. Extensive measurements were made in and around the separation point and within the junction vortex system, both very close to the floor and to the leading edge of the body generating the vortex system. Real-time smoke visualizations confirmed a region of strongly time-variant flow with large changes in the scale and position of the principal vortex structure. The extensive velocity field data are correlated with high quality surface visualizations and surface pressure measurements. The mean velocity measurements show one large well-defined vortex structure and one singular saddle point of separation on the symmetry plane. The transverse vorticity field computed from the extensive velocity field suggests a very strong but small second, counter rotating vortex located in the extreme corner formed by the floor and leading edge of the body. The surface flow visualization suggests only one clear separation line. The single pair of counter rotating vortices revealed by these detailed LDV velocity measurements is in agreement with two independent studies which used multiple orifice pressure probes. This measured two vortex model is not in agreement with the frequently pictured four vortex flow model, inferred from surface flow visualizations, showing two pairs of counter rotating vortices.

Asymmetrical Lateral Jet Interaction on a Slender Body in Supersonic Flow

2014 ◽  
Vol 565 ◽  
pp. 107-112
Author(s):  
Shi Jie Luo
Keyword(s):  
Supersonic Flow ◽  
Total Pressure ◽  
Angle Of Attack ◽  
The Body ◽  
Slender Body ◽  
Far Field ◽  
Field Interaction ◽  
Jet Interaction ◽  
Pressure Distributions ◽  
Highly Nonlinear

The lateral jet interaction on a slender body with rudders in supersonic flow had been investigated by numerical simulation, when the lateral jet is not in the longitudinal symmetry plane. It was called Asymmetrical lateral jet interaction in this paper. The flow features of jet interaction flowfield on the surface of the body or in the space far from the surface at different angles of attack and total pressure of jet was analyzed. As a result, the lateral jet interaction disturbed the pressure distributions of the slender body, and it was divided into near-field interaction near jet and far-field interaction aft-body on the basis of distance to jet. With the variety of the angle of attack and total pressure of jet, the pressure distributions at the aft-body change tempestuously, thereby the normal and lateral load will be from positive to negative, or reverse. The results also showed that the far-field interaction played a major role in the lateral jet interaction on a slender body in supersonic flow. The far-field interaction was caused by the changing of the outflow direction and intensity. Besides, the force/moment amplification factors presented highly nonlinear with the variety of angle of attack and total pressure of jet.

The Supersonic Flow Past a Slender Ducted Body of Revolution with an Annular Intake

1950 ◽  
Vol 1 (4) ◽  
pp. 305-318
Author(s):  
G. N. Ward
Keyword(s):  
Supersonic Flow ◽  
Velocity Potential ◽  
Operational Calculus ◽  
The Body ◽  
Body Of Revolution ◽  
Internal Flows ◽  
Flow Past ◽  
External Forces ◽  
Internal Pressures ◽  
Slender Body Of Revolution

SummaryThe approximate supersonic flow past a slender ducted body of revolution having an annular intake is determined by using the Heaviside operational calculus applied to the linearised equation for the velocity potential. It is assumed that the external and internal flows are independent. The pressures on the body are integrated to find the drag, lift and moment coefficients of the external forces. The lift and moment coefficients have the same values as for a slender body of revolution without an intake, but the formula for the drag has extra terms given in equations (32) and (56). Under extra assumptions, the lift force due to the internal pressures is estimated. The results are applicable to propulsive ducts working under the specified condition of no “ spill-over “ at the intake.

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