Reynolds number effects on the vortical-flow structure generated by a double-delta wing

2000 ◽  
Vol 28 (3) ◽  
pp. 206-216 ◽  
Author(s):  
S. K. Hebbar ◽  
M. F. Platzer ◽  
A. E. Fritzelas
Keyword(s):  
Reynolds Number ◽  
Flow Structure ◽  
Delta Wing ◽  
Vortical Flow ◽  
Reynolds Number Effects ◽  
Double Delta Wing

Numerical Investigations for the Effect of Slender Body on Dynamic Rolling Characteristics of a 80°/60° Double Delta Wing

2013 ◽  
Vol 444-445 ◽  
pp. 286-292
Author(s):  
Bing Han ◽  
Min Xu ◽  
Xi Pei ◽  
Xiao Min An
Keyword(s):  
Stokes Equations ◽  
Delta Wing ◽  
Time Lag ◽  
Slender Body ◽  
Vortical Flow ◽  
Navier Stokes ◽  
Rolling Motion ◽  
Navier Stokes Equations ◽  
Lag Effect ◽  
Double Delta Wing

The effect of slender body on the rolling characteristics of a double delta wing is found by comparing the numerical simulation results of the double delta wing and wing-body configuration. The coupled computation system solving the Navier-Stokes equations and the rolling motion equation alternatively to obtain the unsteady vortical flow around the two configurations while rolling. The results conclusively showed the upwash effect of the slender body enhanced the energy of strake vortex and merged vortex.The aerodynamic lag of double delta wing is weak, contrarily, the time lag effect of the wing-body configuration is significant. The asymmetry vortices structure nearby the trailing edge are believed to be the main reason for the unsteady time lag effect.

Reynolds Number Effects on Flow Topology Above Blunt-edged Delta Wing VFE-2 Configurations

2015 ◽  
Author(s):  
Mazuriah Said ◽  
Shabudin B. Mat ◽  
Shuhaimi Mansor ◽  
Ainullotfi Abdul-Latif ◽  
Tholudin Mat Lazim
Keyword(s):  
Reynolds Number ◽  
Delta Wing ◽  
Flow Topology ◽  
Reynolds Number Effects

Flow Structure on Nonslender Delta Wing: Reynolds Number Dependence and Flow Control

AIAA Journal ◽  
2016 ◽  
Vol 54 (3) ◽  
pp. 880-897 ◽  
Author(s):  
Mohammadreza Zharfa ◽  
Ilhan Ozturk ◽  
Mehmet Metin Yavuz
Keyword(s):  
Reynolds Number ◽  
Flow Control ◽  
Flow Structure ◽  
Delta Wing ◽  
Reynolds Number Dependence

Analysis and direct numerical simulation of the flow at a gravity-current head. Part 1. Flow topology and front speed for slip and no-slip boundaries

2000 ◽  
Vol 418 ◽  
pp. 189-212 ◽  
Author(s):  
CARLOS HÄRTEL ◽  
ECKART MEIBURG ◽  
FRIEDER NECKER
Keyword(s):  
Reynolds Number ◽  
Stagnation Point ◽  
Flow Structure ◽  
Gravity Current ◽  
Three Dimensional ◽  
Head Part ◽  
Two Dimensional ◽  
Flow Topology ◽  
Reynolds Number Effects ◽  
Dimensional Simulation

Direct numerical simulations are performed of gravity-current fronts in the lock-exchange configuration. The case of small density differences is considered, where the Boussinesq approximations can be adopted. The key objective of the investigation is a detailed analysis of the flow structure at the foremost part of the front, where no previous high-resolution data were available. For the simulations, high-order numerical methods are used, based on spectral and spectral-element discretizations and compact finite differences. A three-dimensional simulation is conducted of a front spreading along a no-slip boundary at a Reynolds number of about 750. The simulation exhibits all features typically observed in experimental flows near the gravity-current head, including the lobe-and-cleft structure at the leading edge. The results reveal that the flow topology at the head differs from what has been assumed previously, in that the foremost point is not a stagnation point in a translating system. Rather, the stagnation point is located below and slightly behind the foremost point in the vicinity of the wall. The relevance of this finding for the mechanism behind the lobe-and-cleft instability is discussed. In order to explore the high-Reynolds-number regime, and to assess potential Reynolds-number effects, two-dimensional simulations are conducted for Reynolds numbers up to about 30 000, for both no-slip and slip (i.e. shear-stress free) boundaries. It is shown that although quantitative Reynolds-number effects persist over the whole range examined, no qualitative changes in the flow structure at the head can be observed. A comparison of the two-dimensional results with laboratory data and the three-dimensional simulation provides evidence that a two-dimensional model is able to capture essential features of the flow at the head. The simulations also show that for the free-slip case the shape of the head agrees closely with the classical inviscid theory of Benjamin.

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