Three-dimensional large eddy simulation and vorticity analysis of unsteady cavitating flow around a twisted hydrofoil

2013 ◽  
Vol 25 (4) ◽  
pp. 510-519 ◽  
Author(s):  
Bin Ji ◽  
Xian-wu Luo ◽  
Xiao-xing Peng ◽  
Yu-lin Wu
Keyword(s):  
Large Eddy Simulation ◽  
Three Dimensional ◽  
Cavitating Flow ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Vorticity Analysis ◽  
Twisted Hydrofoil ◽  
Unsteady Cavitating Flow

Numerical Simulation of Cavity Shedding from a Three-Dimensional Twisted Hydrofoil and Induced Pressure Fluctuation by Large-Eddy Simulation

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Xianwu Luo ◽  
Bin Ji ◽  
Xiaoxing Peng ◽  
Hongyuan Xu ◽  
Michihiro Nishi
Keyword(s):  
Large Eddy Simulation ◽  
Pressure Fluctuation ◽  
Three Dimensional ◽  
Cavitating Flow ◽  
Numerical Results ◽  
Central Plane ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Cavity Shedding ◽  
Twisted Hydrofoil

Simulation of cavity shedding around a three-dimensional twisted hydrofoil has been conducted by large eddy simulation coupling with a mass transfer cavitation model based on the Rayleigh-Plesset equation. From comparison of the numerical results with experimental observations, e.g., cavity shedding evolution, it is validated that the unsteady cavitating flow around a twisted hydrofoil is reasonably simulated by the proposed method. Numerical results clearly reproduce the cavity shedding process, such as cavity development, breaking-off and collapsing in the downstream. Regarding vapor shedding in the cavitating flow around three-dimensional foils, it is primarily attributed to the effect of the re-entrant flow consisting of a re-entrant jet and a pair of side-entrant jets. Formation of the re-entrant jet in the rear part of an attached cavity is affected by collapse of the last shedding vapor. Numerical results also show that the cavity shedding causes the surface pressure fluctuation of the hydrofoil and the force vibration. Accompanying the cavity evolution, the wave of pressure fluctuation propagates in two directions, namely, from the leading edge of the foil to the trailing edge and from the central plane to the side of the hydrofoil along the span. It is seen that the large pressure fluctuation occurs at the central part of the hydrofoil, where the flow incidence is larger.

scholarly journals Cloud Cavitating Flow Over a Submerged Axisymmetric Projectile and Comparison Between Two-Dimensional RANS and Three-Dimensional Large-Eddy Simulation Methods

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Yiwei Wang ◽  
Chenguang Huang ◽  
Xin Fang ◽  
Xianian Yu ◽  
Xiaocui Wu ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Cavitating Flow ◽  
Two Dimensional ◽  
Cloud Cavitation ◽  
Cavity Collapse ◽  
Eddy Simulation ◽  
2D Simulation ◽  
Large Eddy

For the cloud cavitation around slender axisymmetric projectiles, a two-dimensional (2D) numerical method was based on the mixture approach with Singhal cavitation model and modified renormalization-group (RNG) k–ε turbulence model, and a three-dimensional (3D) method was established with large-eddy simulation (LES) and volume of fraction (VOF) approach. The commercial computational fluid dynamic (CFD) software fluent is used for the 2D simulation, and the open source code OpenFOAM is adopted for the 3D calculation. Experimental and numerical results were presented on a typical case, in which the projectile moves with a quasi-constant axial speed. Simulation results agree well with experimental results. An analysis of the evolution of cavitating flow was performed, and the related physical mechanism was discussed. Results demonstrate that shedding cavity collapse plays an important role in the generation and acceleration of re-entry jet, which is the main reason for the instability of cloud cavitation. The 2D Reynolds-Averaged Navier–Stokes (RANS) method can represent the physical phenomena effectively. The 3D LES method can give an efficient simulation on the shedding vortices, and considerable accurate shapes of shedding cavities are captured.

Large Eddy Simulation of Cross Flow in Pipe Junction

2018 ◽  
Author(s):  
Jiajun Chen ◽  
Yue Sun ◽  
Hang Zhang ◽  
Dakui Feng ◽  
Zhiguo Zhang
Keyword(s):  
Large Eddy Simulation ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Cross Flow ◽  
Exciting Force ◽  
Navier Stokes ◽  
Pipe Network ◽  
Eddy Simulation ◽  
Large Eddy

Mixing in pipe junctions can play an important role in exciting force and distribution of flow in pipe network. This paper investigated the cross pipe junction and proposed an improved plan, Y-shaped pipe junction. The numerical study of a three-dimensional pipe junction was performed for calculation and improved understanding of flow feature in pipe. The filtered Navier–Stokes equations were used to perform the large-eddy simulation of the unsteady incompressible flow in pipe. From the analysis of these results, it clearly appears that the vortex strength and velocity non-uniformity of centerline, can be reduced by Y-shaped junction. The Y-shaped junction not only has better flow characteristic, but also reduces head loss and exciting force. The results of the three-dimensional improvement analysis of junction can be used in the design of pipe network for industry.

Large eddy simulation of stratified mixing in a three-dimensional lock-exchange system

2009 ◽  
Vol 26 (3-4) ◽  
pp. 134-155 ◽  
Author(s):  
Tamay M. Özgökmen ◽  
Traian Iliescu ◽  
Paul F. Fischer
Keyword(s):  
Large Eddy Simulation ◽  
Three Dimensional ◽  
Exchange System ◽  
Eddy Simulation ◽  
Large Eddy
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