An improved Navier-Stokes/full-potential coupled analysis for rotors

1994 ◽  
Author(s):  
C. Berezin ◽  
L. Sankar
Keyword(s):  
Navier Stokes ◽  
Coupled Analysis ◽  
Full Potential

Three-dimensional Navier-Stokes/full-potential coupled analysis for viscous transonic flow

AIAA Journal ◽  
1993 ◽  
Vol 31 (10) ◽  
pp. 1857-1862 ◽  
Author(s):  
Lakshmi N. Sankar ◽  
Bala K. Bharadvaj ◽  
Fu-Lin Tsung
Keyword(s):  
Transonic Flow ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Coupled Analysis ◽  
Full Potential

A Navier-Stokes/full potential/free wake method for rotor flows

1997 ◽  
Author(s):  
Mert Berkman ◽  
Lakshmi Sankar ◽  
Charles Berezin ◽  
Michael Torok ◽  
Mert Berkman ◽  
...  
Keyword(s):  
Navier Stokes ◽  
Full Potential ◽  
Free Wake

Navier-Stokes/Full Potential/Free-Wake Method for Rotor Flows

1997 ◽  
Vol 34 (5) ◽  
pp. 635-640 ◽  
Author(s):  
Mert E. Berkman ◽  
Lakshmi N. Sankar ◽  
Charles R. Berezin ◽  
Michael S. Torok
Keyword(s):  
Navier Stokes ◽  
Full Potential ◽  
Free Wake

THE WING-BODY AEROELASTIC ANALYSES USING THE INVERSE DESIGN METHOD

2010 ◽  
Vol 24 (13) ◽  
pp. 1479-1482
Author(s):  
SEUNG JUN LEE ◽  
DONG-KYUN IM ◽  
IN LEE ◽  
JANG-HYUK KWON
Keyword(s):  
Design Method ◽  
The Body ◽  
Inverse Design ◽  
Navier Stokes ◽  
Full Potential ◽  
Small Disturbance ◽  
Body Effect ◽  
Flow Equations ◽  
Applicable Range ◽  
Inverse Design Method

Flutter phenomenon is one of the most dangerous problems in aeroelasticity. When it occurs, the aircraft structure can fail in a few second. In recent aeroelastic research, computational fluid dynamics (CFD) techniques become important means to predict the aeroelastic unstable responses accurately. Among various flow equations like Navier-Stokes, Euler, full potential and so forth, the transonic small disturbance (TSD) theory is widely recognized as one of the most efficient theories. However, the small disturbance assumption limits the applicable range of the TSD theory to the thin wings. For a missile which usually has small aspect ratio wings, the influence of body aerodynamics on the wing surface may be significant. Thus, the flutter stability including the body effect should be verified. In this research an inverse design method is used to complement the aerodynamic deficiency derived from the fuselage. MGM (modified Garabedian-McFadden) inverse design method is used to optimize the aerodynamic field of a full aircraft model. Furthermore, the present TSD aeroelastic analyses do not require the grid regeneration process. The MGM inverse design method converges faster than other conventional aerodynamic theories. Consequently, the inverse designed aeroelastic analyses show that the flutter stability has been lowered by the body effect.

Prediction of Hydrodynamic Damping of Moored Offshore Structures Using CFD

2019 ◽  
Author(s):  
Changqing Jiang ◽  
Ould el Moctar ◽  
Thomas E. Schellin
Keyword(s):  
Offshore Structures ◽  
Least Square ◽  
Navier Stokes ◽  
Coupled Analysis ◽  
Total System ◽  
Mooring System ◽  
Restoring Force ◽  
Hydrodynamic Damping ◽  
Restoring Forces ◽  
Decay Tests

Abstract Usually, mooring system restoring forces acting on floating offshore structures are obtained from a quasi-static mooring model alone or from a coupled analysis based on potential flow solvers that do not always consider nonlinear mooring-induced phenomena or fluid-structure interactions and the associated viscous damping effects. By assuming that only the mooring system influences the restoring force characteristics, the contribution of mooring-induced damping to total system damping is neglected. This paper presents a technique to predict hydrodynamic damping of moored structures based on coupling the dynamic mooring model with a Reynolds-averaged Navier-Stokes (RANS) equations solver. We obtained hydrodynamic damping coefficients using a least-square algorithm to fit the time trace of decay tests. We analyzed a moored offshore buoy and validated our predictions against experimental measurements. The mooring system consisted of three catenary chains. The analyzed response comprised the decaying oscillating buoy motions, the natural periods, and the associated linear and quadratic damping characteristics. Predicted motions, natural periods, and hydrodynamic damping generally well agreed to comparable experimental data.

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