On the Stability of a Circular Cylinder at Hypersonic Speeds

10.7249/p723 ◽  
1955 ◽  
Keyword(s):  
Circular Cylinder ◽  
Hypersonic Speeds ◽  
The Stability

Base Flow of Circular Cylinder at Hypersonic Speeds

AIAA Journal ◽  
2016 ◽  
Vol 54 (2) ◽  
pp. 458-468 ◽  
Author(s):  
Gisu Park ◽  
Sudhir L. Gai ◽  
Andrew J. Neely
Keyword(s):  
Circular Cylinder ◽  
Base Flow ◽  
Hypersonic Speeds

Global Stability Analysis of the Wake behind a Circular Cylinder Based on the POD-Chiba Method

2011 ◽  
Vol 137 ◽  
pp. 72-76
Author(s):  
Wei Zhang ◽  
Xian Wen ◽  
Yan Qun Jiang
Keyword(s):  
Stability Analysis ◽  
Circular Cylinder ◽  
Global Stability ◽  
Dimensional Model ◽  
Global Stability Analysis ◽  
The Stability ◽  
Low Dimensional ◽  
Proper Orthogonal ◽  
Calculated Amount ◽  
Good Agreement

A proper orthogonal decomposition (POD) method is applied to study the global stability analysis for flow past a stationary circular cylinder. The flow database at Re=100 is obtained by CFD software, i.e. FLUENT, with which POD bases are constructed by a snapshot method. Based on the POD bases, a low-dimensional model is established for solving the two-dimensional incompressible NS equations. The stability of the flow solution is evaluated by a POD-Chiba method in the way of the eigensystem analysis for the velocity disturbance. The linear stability analysis shows that the first Hopf bifurcation takes place at Re=46.9, which is in good agreement with available results by other high-order accurate stability analysis methods. However, the calculated amount of POD is little, which shows the availability and advantage of the POD method.

Laminar Near Wake of a Circular Cylinder at Hypersonic Speeds

AIAA Journal ◽  
2010 ◽  
Vol 48 (1) ◽  
pp. 236-248 ◽  
Author(s):  
Gisu Park ◽  
Sudhir L. Gai ◽  
Andrew J. Neely
Keyword(s):  
Circular Cylinder ◽  
Near Wake ◽  
Hypersonic Speeds

An Analysis of the Static and Dynamic Stability of an Hypersonic Transport Aircraft Longitudinal Motion Flying at Hypersonic Speeds and Various Heights

2012 ◽  
Author(s):  
D. Mclean ◽  
Z.A. Zaludin ◽  
P.R. Arora
Keyword(s):  
Mathematical Model ◽  
Dynamic Stability ◽  
Static Stability ◽  
Longitudinal Motion ◽  
Transport Aircraft ◽  
Static And Dynamic Stability ◽  
Hypersonic Speeds ◽  
Scramjet Engine ◽  
The Stability ◽  
Engine Condition

Suatu kajian tentang kestabilan statik dan dinamik pesawat pengangkutan hipersonik hipotesis telah dilakukan dengan menggunakan model matematik untuk pergerakan membujur semasa penerbangan di keadaan penerbangan yang berlainan. Hasil daripada analisis kestabilan menunjukkan bahawa pesawat tersebut akan menjadi lebih tidak stabil apabila penerbangan di nombor Mach dan ketinggian yang lebih tinggi daripada keadaan penerbangan nominal. Juga disertakan di sini keadaan enjin scramjet apabila pesawat ini terbang pada kelajuan hipersonik dan ketinggian yang berlainan. Kata kunci: dinamik pesawat; kestabilan dinamik; kestabilan statik; enjin scramjet A study of the static and dynamic stability of an hypothetical hypersonic transport aircraft was conducted based on a mathematical model of the longitudinal motion of the aircraft flying at a number of different flight conditions. The result from the stability analysis has shown that the aircraft becomes even less stable at higher Mach numbers and heights than the nominal flight condition. Also discussed here is the scramjet engine condition when the aircraft was simulated to be flying at hypersonic speeds and different heights. Key words: aircraft dynamics; dynamic stability; static stability; scramjet engine

The effect of confining walls on the stability of the steady wake behind a circular cylinder

1963 ◽  
Vol 17 (4) ◽  
pp. 546-550 ◽  
Author(s):  
F. H. Shair* ◽  
A. S. Grove ◽  
E. E. Petersen ◽  
A. Acrivos
Keyword(s):  
Experimental Investigation ◽  
Circular Cylinder ◽  
Experimental Equipment ◽  
Laminar Wake ◽  
The Stability ◽  
Steady Laminar

The results of an experimental investigation are presented to show that the stability of the steady laminar wake behind a circular cylinder is strongly influenced by the proximity of the walls of the confining experimental equipment.

Centrifugal waves

1960 ◽  
Vol 7 (3) ◽  
pp. 340-352 ◽  
Author(s):  
O. M. Phillips
Keyword(s):  
Free Surface ◽  
Angular Velocity ◽  
Circular Cylinder ◽  
Rigid Body ◽  
Water Depth ◽  
Frequency Equation ◽  
Rigid Rotation ◽  
Body Motion ◽  
Small Perturbations ◽  
The Stability

When a hollow circular cylinder with its axis horizontal is partially filled with water and rotated rapidly about its axis, an almost rigid-body motion results with an interior free surface. The emotion is analysed assuming small perturbations to a rigid rotation, and a criterion is found for the stability of the motion. This is confirmed experimentally under varying conditions of water depth and angular velocity of the cylinder. The modes of oscillation (centrifugal waves) of the free surface are examined and a frequency equation deduced. Two particular modes are considered in detail, and satisfactory agreement is found with the frequencies observed.

Experimental Study on the Stability of the Flow Behind an Accelerating Circular Cylinder

2007 ◽  
Author(s):  
A. Inasawa ◽  
K. Toda ◽  
M. Asai
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Critical Reynolds Number ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Cylinder Wake ◽  
Global Instability ◽  
The Stability ◽  
Dimensional Instability ◽  
Wake Oscillation

Disturbance growth in the wake of a circular cylinder moving at a constant acceleration is examined experimentally. The cylinder is installed on a carriage moving in the still air. The results show that the critical Reynolds number for the onset of the global instability leading to a self-sustained wake oscillation increases with the magnitude of acceleration, while the Strouhal number of the growing disturbance at the critical Reynolds number is not strongly dependent on the magnitude of acceleration. It is also found that with increasing the acceleration, the Ka´rma´n vortex street remains two-dimensional even at the Reynolds numbers around 200 where the three-dimensional instability occurs to lead to the vortex dislocation in the case of cylinder moving at constant velocity or in the case of cylinder wake in the steady oncoming flow.

scholarly journals On the Effects of Circulation around a Circle on the Stability of a Thomson Vortex N-gon

Mathematics ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 1033
Author(s):  
Leonid Kurakin ◽  
Irina Ostrovskaya
Keyword(s):  
Circular Cylinder ◽  
Hamiltonian Systems ◽  
Nonlinear Stability ◽  
Vortex Dynamics ◽  
Stability Problem ◽  
Orbital Stability ◽  
Stability And Instability ◽  
The Stability ◽  
Parameter Values ◽  
Linear Setting

The stability problem of the stationary rotation of N identical point vortices is considered. The vortices are located on a circle of radius R 0 at the vertices of a regular N-gon outside a circle of radius R. The circulation Γ around the circle is arbitrary. The problem has three parameters N, q, Γ , where q = R 2 / R 0 2 . This old problem of vortex dynamics is posed by Havelock (1931) and is a generalization of the Kelvin problem (1878) on the stability of a regular vortex polygon (Thomson N-gon) on the plane. In the case of Γ = 0 , the problem has already been solved: in the linear setting by Havelock, and in the nonlinear setting in the series of our papers. The contribution of this work to the solution of the problem consists in the analysis of the case of non-zero circulation Γ ≠ 0 . The linearization matrix and the quadratic part of the Hamiltonian are studied for all possible parameter values. Conditions for orbital stability and instability in the nonlinear setting are found. The parameter areas are specified where linear stability occurs and nonlinear analysis is required. The nonlinear stability theory of equilibria of Hamiltonian systems in resonant cases is applied. Two resonances that lead to instability in the nonlinear setting are found and investigated, although stability occurs in the linear approximation. All the results obtained are consistent with those known for Γ = 0 . This research is a necessary step in solving similar problems for the case of a moving circular cylinder, a model of vortices inside an annulus, and others.

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