Two-Dimensional Apparent Masses for Cross-Flow Sections of Wing-Store Configurations

1982 ◽  
Vol 49 (3) ◽  
pp. 471-475
Author(s):  
M.-K. Huang
Keyword(s):  
Approximate Method ◽  
Cross Flow ◽  
Slender Body ◽  
Two Dimensional ◽  
Aerodynamic Stability ◽  
Slender Body Theory ◽  
Rolling Moment ◽  
Stability Derivatives ◽  
The Cross ◽  
Body Theory

On the basis of the assumption that the external stores are small compared with the wing, an approximate method has been developed for estimation of two-dimensional apparent masses for the cross-flow sections of wing-store combinations. The results obtained may be applicable to the analysis of the effects of the stores on the aerodynamic stability derivatives in slender-body theory. The theory has also been applied to estimate the rolling moment due to sideslip for high-wing configurations. The presented results are in agreement with those of other investigations.

Lateral Force and Yaw Moment on a Slender Body in Forward Motion at a Yaw Angle

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Ronald W. Yeung ◽  
Robert K. M. Seah ◽  
John T. Imamura
Keyword(s):  
Viscous Flow ◽  
Cross Flow ◽  
Slender Body ◽  
Order Effects ◽  
Forward Motion ◽  
Slender Body Theory ◽  
Flow Equations ◽  
The Cross ◽  
Yaw Angle ◽  
Body Theory

This paper presents a solution method for obtaining the lateral hydrodynamic forces and moments on a submerged body translating at a yaw angle. The method is based on the infinite-fluid formulation of the free-surface random-vortex method (FSRVM), which is reformulated to include the use of slender-body theory. The resulting methodology is given the name: slender-body FSRVM (SB-FSRVM). It utilizes the viscous-flow capabilities of FSRVM with a slender-body theory assumption. The three-dimensional viscous-flow equations are first shown to be reducible to a sequence of two-dimensional viscous-fluid problems in the cross-flow planes with the lowest-order effects from the forward velocity included in the cross-flow plane. The theory enables one to effectively analyze the lateral forces and yaw moments on a body undergoing prescribed forward motion with the possible occurrence of cross-flow separation. Applications are made to several cases of body geometry that are in steady forward motion, but at a yawed orientation. These include the case of a long “cone-tail” body. Comparisons are made with existing data where possible.

Separated Flow About a Slender Body in Forward and Lateral Motion

2008 ◽  
Author(s):  
Ronald W. Yeung ◽  
Robert K. M. Seah ◽  
John T. Imamura
Keyword(s):  
Viscous Flow ◽  
Cross Flow ◽  
Separated Flow ◽  
Vortex Method ◽  
Slender Body ◽  
Order Effects ◽  
Forward Motion ◽  
Slender Body Theory ◽  
Flow Equations ◽  
Body Theory

This paper presents a solution method for obtaining the hydrodynamic forces and moments on a submerged body translating at a yaw angle. The method is based on the infinite-fluid formulation of the Free Surface Random Vortex Method (FSRVM), which is re-formulated to include the use of slender-body theory. The resulting methodology is given the name: Slender-Body FSRVM (SB-FSRVM). It utilizes the viscous-flow capabilities of FSRVM with a slender-body theory assumption. The three-dimensional viscous-flow equations are first shown to be reducible to a sequence of two-dimensional viscous-fluid problems in the cross-flow planes with the lowest-order effects from the forward velocity included. The theory enables one to analyze effectively the lateral forces and yaw moments on a body undergoing prescribed forward motion with the possible occurrence of flow separation. Applications are made to several cases of body geometry that are in steady forward motion, but at a yawed orientation. These include the case of a long “cone-tail” body. Comparisons are made with existing data where possible.

The flow field near the centre of a rolled-up vortex sheet

1967 ◽  
Vol 30 (1) ◽  
pp. 177-196 ◽  
Author(s):  
K. W. Mangler ◽  
J. Weber
Keyword(s):  
Delta Wing ◽  
Present Report ◽  
Vortex Sheet ◽  
Slender Body ◽  
Two Dimensional ◽  
Slender Body Theory ◽  
Vortex Sheets ◽  
Dimensional Flow ◽  
Two Dimensional Flow ◽  
Body Theory

Most of the existing methods for calculating the inviscid flow past a delta wing with leading-edge vortices are based on slender-body theory. When these vortices are represented by rolled-up vortex sheets in an otherwise irrotational flow, some of the assumptions of slender-body theory are violated near the centres of the spirals. The aim of the present report is to describe for the vortex core an alternative method in which only the assumption of a conical velocity field is made. An asymptotic solution valid near the centre of a rolled-up vortex sheet is derived for incompressible flow. Further asymptotic solutions are determined for two-dimensional flow fields with vortex sheets which vary with time in such a manner that the sheets remain similar in shape. A particular two-dimensional flow corresponds to the slender theory approximation for conical sheets.

scholarly journals Software development for subsonic aircraft’s unsteady longitudinal stability derivatives calculation

2005 ◽  
Vol 32 (4) ◽  
pp. 319-340 ◽  
Author(s):  
Nikola Maricic
Keyword(s):  
Method Of Images ◽  
Lattice Method ◽  
Aerodynamic Stability ◽  
Slender Body Theory ◽  
Stability Derivatives ◽  
Doublet Lattice Method ◽  
Body Theory ◽  
General Configuration ◽  
Finite Element Methodology ◽  
Good Agreement

Subsonic general configuration aircrafts? unsteady longitudinal aerodynamic stability derivatives can be estimated using finite element methodology based on the Doublet Lattice Method (DLM), the Slender Body Theory (SBT) and the Method of Images (MI). Applying this methodology, software DERIV is developed. The obtained results from DERIV are compared to NASTRAN examples HA21A and HA75H. A good agreement is achieved.

scholarly journals Cavity flow past a slender pointed hydrofoil

1961 ◽  
Vol 11 (2) ◽  
pp. 187-208 ◽  
Author(s):  
E. Cumberbatch ◽  
T. Y. Wu
Keyword(s):  
Angle Of Attack ◽  
Cross Flow ◽  
The Body ◽  
Two Dimensional ◽  
Cross Sectional ◽  
Slender Body Theory ◽  
Flow Past ◽  
Two Dimensional Flow ◽  
Cavity Boundary ◽  
The Cross

A slender-body theory for the flow past a slender, pointed hydrofoil held at a small angle of attack to the flow, with a cavity on the upper surface, has been worked out. The approximate solution valid near the body is seen to be the sum of two components. The first consists of a distribution of two-dimensional sources located along the centroid line of the cavity to represent the variation of the cross-sectional area of the cavity. The second component represents the cross-flow perpendicular to the centroid line. It is found that over the cavity boundary which envelops a constant pressure region, the magnitude of the cross-flow velocity is not constant, but varies to a moderate extent. With this variation neglected only in the neighbourhood of the hydrofoil, the cross-flow is solved by adopting the Riabouchinsky model for the two-dimensional flow. The lift is then calculated by intergrating the pressure along the chord; the dependence of the lift on cavitation number and angle of attack is shown for a specific case of the triangular plan form.

Sway, Roll, and Yaw Motion Coefficients Based on a Forward-Speed Slender-Body Theory—Part 1

1981 ◽  
Vol 25 (01) ◽  
pp. 8-15
Author(s):  
Armin Walter Troesch
Keyword(s):  
Cross Coupling ◽  
Added Mass ◽  
Numerical Results ◽  
Slender Body ◽  
Forward Speed ◽  
Coupling Coefficients ◽  
Slender Body Theory ◽  
Damping Coefficients ◽  
The Cross ◽  
Body Theory

The added-mass and damping coefficients for sway, roll, and yaw are formulated for a ship with forward speed. The theory is similar to that given by Ogilvie and Tuck (1969) for the heave and pitch coefficients of a slender ship. Numerical results are presented for the cross-coupling coefficients.

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