scholarly journals Numerical investigation of wake structures of an atmospheric entry capsule by modal analysis

2019 ◽  
Vol 31 (7) ◽  
pp. 074105 ◽  
Author(s):  
Yuya Ohmichi ◽  
Kenji Kobayashi ◽  
Masahiro Kanazaki
Keyword(s):  
Modal Analysis ◽  
Numerical Investigation ◽  
Atmospheric Entry

scholarly journals Warped Accretion Discs

2003 ◽  
Vol 208 ◽  
pp. 385-386
Author(s):  
D. Chakrabarty ◽  
J. Murray ◽  
G.A. Wynn ◽  
A.R. King
Keyword(s):  
Magnetic Field ◽  
Modal Analysis ◽  
Numerical Investigation ◽  
Fourier Transforms ◽  
Small Difference ◽  
Accretion Discs ◽  
Stellar Systems ◽  
Hydrodynamic Simulations ◽  
Companion Star ◽  
The Magnetic Field

In this article we report the results of our numerical investigation of warped accretion discs in binary stellar systems. We perform complete 3-D hydrodynamic simulations of binary discs. The disc is rendered unstable to the warp mode under the action of the magnetic field of the companion star in the binary. The disc thus warped is noted to undergo retrograde precession with a precession period just slightly less than the binary period. This small difference in periods can explain the phenomenon of negative superhumps observed in a number of binaries. Besides the modal analysis based on Fourier transforms, warps were also studied by a simple and robust technique that we developed; this is based on an analysis of the azimuthal distributions of particles that lie above and below the mid-plane of the disc.

scholarly journals A Numerical Investigation on Stress Modal Analysis of Composite Laminated Thin Plates

Aerospace ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 63
Author(s):  
Yadong Zhou ◽  
Youchao Sun ◽  
Weili Zeng
Keyword(s):  
Modal Analysis ◽  
Numerical Investigation ◽  
Stress Reduction ◽  
Composite Laminates ◽  
Dynamic Properties ◽  
Stress Component ◽  
High Strength ◽  
Laminated Plates ◽  
Thin Plates ◽  
Mode Shapes

Because of the light weight and high strength, composite laminates have many advantages in aircraft structures; however, they are frequently subjected to severe dynamic loadings during flight. To understand the dynamic properties of composite laminated thin plates at the stress scale, this paper studies the stress modal analysis (SMA) of composite laminated thin plates by finite element method (FEM). Firstly, the basic theory on SMA of composite laminates was given from the classical displacement modal analysis. Secondly, a square laminated thin plate was numerically studied to obtain some distribution laws of the stress mode shapes (SMSs) from the layup and stress component perspectives. Then, based on the characteristics of SMSs in different plies, a modified layup configuration was conducted for possible lower magnitude and more uniform distributions of SMSs. Results indicate that ±45° layups can improve the performance of SMSs of the square plate, without excessively decreasing the modal frequencies. Such fact manifests that ±45° layups are critically vital for the dynamic stress reduction of the square composite laminated plates. Modal participation factor and strain energy were evaluated to assist the determination of critical modes. Lastly, the aspect ratio of the composite plate on layup design was considered. Numerical investigation in this study can serve as a preliminary step of SMSs perspective for the analysis and optimization of dynamic composite laminates.

Modal Analysis of Turbulent Flow near an Inclined Bank–Longitudinal Structure Junction

2021 ◽  
Vol 147 (3) ◽  
pp. 04020100
Author(s):  
Nasser Heydari ◽  
Panayiotis Diplas ◽  
J. Nathan Kutz ◽  
Soheil Sadeghi Eshkevari
Keyword(s):  
Turbulent Flow ◽  
Modal Analysis ◽  
Longitudinal Structure
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