Generalized aerodynamic forces on an oscillating cylindrical shell -Subsonic and supersonic flow.

AIAA Journal ◽  
1966 ◽  
Vol 4 (4) ◽  
pp. 607-610 ◽  
Author(s):  
EARL H. DOWELL ◽  
SHEILA E. WIDNALL
Keyword(s):  
Cylindrical Shell ◽  
Supersonic Flow ◽  
Aerodynamic Forces

scholarly journals Dynamic instability of a compound nanocomposite shell

2021 ◽  
Vol 27 (5) ◽  
pp. 60-70
Author(s):  
N.H. Sakhno ◽  
◽  
K.V. Avramov ◽  
B.V. Uspensky ◽  
◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Cylindrical Shell ◽  
Supersonic Flow ◽  
Uniform Distribution ◽  
Critical Pressure ◽  
Natural Frequencies ◽  
Dynamic Instability ◽  
Element Analysis

Free oscillations and dynamic instability due to supersonic airflow pressure are investigated in a functional-gradient compound composite conical-cylindrical shell made of a carbon nanotubes-reinforced material. Nanocomposite materials with a linear distribution of the volumetric fraction of nanotubes over the thickness are considered. Extended mixture rule is used to estimate nanocomposite’s mechanical characteristics. A high-order shear deformation theory is used to represent the shell deformation. The assumed-mode technique, along with a Rayleigh-Ritz method, is applied to obtain the equations of the structure motion. To analyze the compound structure dynamics, a new system of piecewise basic functions is suggested. The pressure of a supersonic flow on the shell is obtained by using the piston theory. An example of the dynamic analysis of a nanocomposite conical-cylindrical shell in the supersonic gas flow is considered. The results of its modal analysis using the Rayleigh-Ritz technique are close to the natural frequencies of the shell obtained by finite element analysis. In this case, finite element analysis can only be used for shells made of material with a uniform distribution of nanotubes over the thickness. The dependence of the natural frequencies of a compound shell on the ratio of the lengths of the conical and cylindrical parts is studied. The dependence of the critical pressure of a supersonic flow on the Mach numbers and the type of carbon nanotubes reinforcement is investigated. Shells with a concentration of nanotubes predominantly near the outer and inner surfaces are characterized by higher values of natural frequencies and critical pressure than the shells with a uniform distribution of nanotubes or with a predominant concentration of nanotubes inside the shell.

scholarly journals Generalized aerodynamic forces on an oscillating cylindrical shell

1966 ◽  
Vol 24 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Earl H. Dowell ◽  
Sheila E. Widnall
Keyword(s):  
Cylindrical Shell ◽  
Aerodynamic Forces

Dynamic Instability of Functionally Graded Carbon Nanotubes-Reinforced Composite Joined Conical-Cylindrical Shell

2021 ◽  
Author(s):  
B. Uspensky ◽  
K. Avramov ◽  
N. Sakhno ◽  
O. Nikonov
Keyword(s):  
Carbon Nanotubes ◽  
Cylindrical Shell ◽  
Supersonic Flow ◽  
Dynamic Instability ◽  
Numerical Study ◽  
Ritz Method ◽  
Functionally Graded ◽  
Reinforced Composite ◽  
Thin Walled ◽  
Functionally Graded Carbon Nanotubes

In this paper, dynamic instability of functionally graded carbon nanotubes (CNTs)-reinforced composite joined conical-cylindrical shell in supersonic flow is analyzed numerically. The higher-order shear deformation theory is applied to describe the stress–strain state of thin-walled structure. The assumed-mode method is used to derive the finite degrees-of-freedom dynamical system, which describes the structure motions. The structure motions are expanded by using the eigenmodes, which are obtained by the Rayleigh–Ritz method. The trial functions, which satisfy the continuity conditions at the cylindrical-cone junction, are used to obtain the eigenmodes. The properties of free vibrations of thin-walled structure are analyzed numerically. The dynamic instability of the joined conical-cylindrical shell in supersonic flow is analyzed using the characteristic exponents. As follows from the numerical study, the dynamic instability is arisen due to the Hopf bifurcation. The dependences of the supersonic flow critical pressure on the Mach number and the type of CNTs distribution are analyzed numerically.

The forces on wing-fuselage combinations in supersonic flow

1960 ◽  
Vol 8 (2) ◽  
pp. 210-226 ◽  
Author(s):  
Joseph H. Clarke
Keyword(s):  
Supersonic Flow ◽  
Reverse Flow ◽  
Mathematical Physics ◽  
Reciprocity Relation ◽  
Hyperbolic Problems ◽  
Aerodynamic Forces ◽  
Relative Ease ◽  
Special Cases

Reverse-flow relations are used to provide convenient expressions for the aerodynamic forces which act on a general wing-fuselage combination in supersonic flow. The drag, lift, spanwise and chordwise lift distributions, and wing moments are treated. Consideration is given to available methods and results, including tables, which apply to the wing-fuselage interference problem, and reverse-flow relations are then employed to effect desirable changes in the detining force expressions by introducing wings or fuselages in the reverse flow. It is shown that the aerodynamic forces can be determined from a solution for the pressure on only the fuselage surface within the domain of dependence of the wing, this region being selected on the basis of relative ease of computation. In some cases the simplification achieved is quite substantial. Certain results in the literature arise naturally as special cases. The reverse-flow theorem is re-examined in the light of the procedure considered, and it is found to be inapplicable in one respect. The difficulty is circumvented by constructing an acceptable configuration which is equipollent to the prescribed one. It appears that the method given is applicable in other linear hyperbolic problems in mathematical physics when bulk or gross information is required and a suitable reciprocity relation can be constructed.

scholarly journals Influence of supersonic flow on nonlinear oscillations of a cylindrical shell

2020 ◽  
Vol 1474 ◽  
pp. 012007
Author(s):  
G Y Baghdasaryan ◽  
M A Mikilyan ◽  
I A Vardanyan ◽  
A V Panteleev
Keyword(s):  
Cylindrical Shell ◽  
Supersonic Flow ◽  
Nonlinear Oscillations

Control of aerodynamic forces on bodies with gas-permeable porous inserts in a supersonic flow

2019 ◽  
Author(s):  
S. G. Mironov ◽  
T. V. Poplavskaya ◽  
I. S. Tsyryulnikov ◽  
S. V. Kirilovskiy
Keyword(s):  
Supersonic Flow ◽  
Aerodynamic Forces
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