Modal decomposition analysis of unsteady viscous liquid sheet flows

2021 ◽  
Vol 33 (9) ◽  
pp. 092117
Author(s):  
Antonio Colanera ◽  
Alessandro Della Pia ◽  
Matteo Chiatto ◽  
Luigi de Luca ◽  
Francesco Grasso
Keyword(s):  
Viscous Liquid ◽  
Decomposition Analysis ◽  
Liquid Sheet ◽  
Modal Decomposition

Linear Instability Analysis of an Annular Swirling Viscous Liquid Jet

2011 ◽  
Vol 66-68 ◽  
pp. 1556-1561 ◽  
Author(s):  
Kai Yan ◽  
Ming Lv ◽  
Zhi Ning ◽  
Yun Chao Song
Keyword(s):  
Viscous Liquid ◽  
Liquid Velocity ◽  
Aerodynamic Force ◽  
Numerical Procedure ◽  
Liquid Sheet ◽  
Linear Instability ◽  
Viscous Force ◽  
Liquid Jet ◽  
Instability Analysis ◽  
Linear Instability Analysis

A three-dimensional linear instability analysis was carried out for an annular swirling viscous liquid jet with solid vortex swirl velocity profile. An analytical form of dispersion relation was derived and then solved by a direct numerical procedure. A parametric study was performed to explore the instability mechanisms that affect the maximum spatial growth rate. It is observed that the liquid swirl enhances the breakup of liquid sheet. The surface tension stabilizes the jet in the low velocity regime. The aerodynamic force intensifies the developing of disturbance and makes the jet unstable. Liquid viscous force holds back the growing of disturbance and the makes the jet stable, especially in high liquid velocity regime.

Modal Decomposition Analysis of Three-Dimensional Transonic Buffet Phenomenon on a Swept Wing

AIAA Journal ◽  
2018 ◽  
Vol 56 (10) ◽  
pp. 3938-3950 ◽  
Author(s):  
Yuya Ohmichi ◽  
Takashi Ishida ◽  
Atsushi Hashimoto
Keyword(s):  
Three Dimensional ◽  
Decomposition Analysis ◽  
Swept Wing ◽  
Modal Decomposition ◽  
Transonic Buffet

On the temporal instability of a two-dimensional viscous liquid sheet

1991 ◽  
Vol 226 ◽  
pp. 425-443 ◽  
Author(s):  
Xianguo Li ◽  
R. S. Tankin
Keyword(s):  
Growth Rate ◽  
Viscous Liquid ◽  
Local Maximum ◽  
Liquid Sheet ◽  
Rate Curve ◽  
Liquid Viscosity ◽  
Number Range ◽  
Liquid Sheets ◽  
Temporal Instability ◽  
Aerodynamic Instability

This paper reports a temporal instability analysis of a moving thin viscous liquid sheet in an inviscid gas medium. The results show that surface tension always opposes, while surrounding gas and relative velocity between the sheet and gas favour, the onset and development of instability. It is found that there exist two modes of instability for viscous liquid sheets – aerodynamic and viscosity-enhanced instability – in contrast to inviscid liquid sheets for which the only mode of instability is aerodynamic. It is also found that axisymmetrical disturbances control the instability process for small Weber numbers, while antisymmetrical disturbances dominate for large Weber numbers. For antisymmetrical disturbances, liquid viscosity, through the Ohnesorge number, enhances instability at small Weber numbers, while liquid viscosity reduces the growth rate and the dominant wavenumber at large Weber numbers. At the intermediate Weber-number range, Liquid viscosity has complicated effects due to the interaction of viscosity-enhanced and aerodynamic instabilities. In this range, the growth rate curve exhibits two local maxima, one corresponding to aerodynamic instability, for which liquid viscosity has a negligible effect, and the other due to viscosity-enhanced instability, which is influenced by the presence and variation of liquid viscosity. For axisymmetrical disturbances, liquid viscosity always reduces the growth rate and the dominant wavenumber, aerodynamic instability always prevails, and although the regime of viscosity-enhanced instability is always present, its growth rate curve does not possess a local maximum.

Spatial instability in annular swirling viscous liquid sheet

2015 ◽  
Vol 27 (2) ◽  
pp. 024101 ◽  
Author(s):  
Kai Yan ◽  
Zhi Ning ◽  
Ming Lü ◽  
Chunhua Sun ◽  
Juan Fu ◽  
...  
Keyword(s):  
Viscous Liquid ◽  
Liquid Sheet ◽  
Spatial Instability

scholarly journals Characterization of the Unsteady Aerodynamics of Optimized Turbine Blade Tips through Modal Decomposition Analysis

2019 ◽  
Vol 4 (2) ◽  
pp. 12
Author(s):  
Bogdan C. Cernat ◽  
Sergio Lavagnoli
Keyword(s):  
High Performance ◽  
Decomposition Analysis ◽  
Unsteady Aerodynamics ◽  
Tip Leakage Flow ◽  
Modal Decomposition ◽  
Time Resolved ◽  
Leakage Flows ◽  
Numerical Predictions ◽  
Blade Tip ◽  
Generation Mechanisms

The present research focused on the analysis of the leakage flows developing from advanced blade tip geometries. The aerodynamic field of a contoured blade tip and of a high-performance rimmed blade were investigated against a baseline squealer rotor. Time-resolved numerical predictions were combined with high-frequency pressure measurements to characterize the tip leakage flow of each tip design. High spatial and temporal resolution measurements provided a detailed representation of the unsteady flow in the near-tip region and at the stage outlet. Numerical computations, based on the nonlinear harmonic method, were employed to assess the unsteady blade row interactions and identify the loss generation mechanisms depending on the tip design. The space- and time-resolved flow field was analysed by modal decomposition to identify the main periodicities of the near-tip and outlet flow and classify the most relevant sources of aerodynamic unsteadiness and entropy generation across the stage.

Effects of liquid and air swirls on the three-dimensional instability of an annular viscous liquid sheet

Fuel ◽  
2021 ◽  
Vol 292 ◽  
pp. 120227
Author(s):  
Xin Hui ◽  
Weijia Qian ◽  
Yuzhen Lin ◽  
Chi Zhang ◽  
Jianchen Wang
Keyword(s):  
Viscous Liquid ◽  
Three Dimensional ◽  
Liquid Sheet ◽  
Dimensional Instability
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