Large Eddy Simulation and theoretical investigations of the transient cavitating vortical flow structure around a NACA66 hydrofoil
TL;DR: In this paper, the cavitating flow around a NACA66 hydrofoil is studied numerically with particular emphasis on understanding the cavitation structures and the shedding dynamics, including the cavity growth, break-off and collapse downstream.
About: This article is published in International Journal of Multiphase Flow.The article was published on 2015-01-01 and is currently open access. It has received 335 citations till now. The article focuses on the topics: Cavitation & Large eddy simulation.
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TL;DR: In this paper, the authors summarized the recent progress for the cavitation study in the hydraulic machinery including turbo-pumps, hydro turbines, etc., and identified the 1-D analysis method, which is identified to be very useful for engineering applications regarding the cavitating flows in inducers, turbine draft tubes, etc.
Abstract: This paper mainly summarizes the recent progresses for the cavitation study in the hydraulic machinery including turbo-pumps, hydro turbines, etc.. Especially, the newly developed numerical methods for simulating cavitating turbulent flows and the achievements with regard to the complicated flow features revealed by using advanced optical techniques as well as cavitation simulation are introduced so as to make a better understanding of the cavitating flow mechanism for hydraulic machinery. Since cavitation instabilities are also vital issue and rather harmful for the operation safety of hydro machines, we present the 1-D analysis method, which is identified to be very useful for engineering applications regarding the cavitating flows in inducers, turbine draft tubes, etc. Though both cavitation and hydraulic machinery are extensively discussed in literatures, one should be aware that a few problems still remains and are open for solution, such as the comprehensive understanding of cavitating turbulent flows especially inside hydro turbines, the unneglectable discrepancies between the numerical and experimental data, etc.. To further promote the study of cavitation in hydraulic machinery, some advanced topics such as a Density-Based solver suitable for highly compressible cavitating turbulent flows, a virtual cavitation tunnel, etc. are addressed for the future works.
296 citations
TL;DR: In this paper, a 3D Lagrangian Coherent Structures (LCS) was used to analyze the dynamics of cavitation-vortex interactions in the Delft twisted hydrofoil.
145 citations
TL;DR: In this paper, the authors investigated the fluid dynamics of a flexible NACA66 hydrofoil in cavitating flows by combined experimental and numerical studies, and the results showed that the cavitation has significant effect on the foil deformation and the unsteady characteristics of the hydroelastic response.
100 citations
TL;DR: In this paper, a sheet to cloud cavitation over a wedge is performed at Reynolds number R e = 200, 000 (based on the wedge height and free stream velocity) and cavitation number σ = 2.1.
98 citations
Cites background from "Large Eddy Simulation and theoretic..."
...Recently, LES has been considered since it can pre- ict flow unsteadiness better without ad–hoc modifications (e.g. nanaskandan and Mahesh, 2015; Bensow and Bark, 2010; Ditakavi et al., 2010; Ji et al., 2015; Wang and Ostoja-Starzewski, 007 )....
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TL;DR: In this paper, a series of experimental observations around hydrofoils are carried out in the cavitation tunnel of the China Ship Scientific Research Center (CSSRC) to illustrate the spatial-temporal evolution of the cloud cavity in detail.
97 citations
References
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TL;DR: In this article, an extended period numerical integration of a baroclinic primitive equation model has been made for the simulation and the study of the dynamics of the atmosphere's general circulation, and the solution corresponding to external gravitational propagation is filtered by requiring the vertically integrated divergence to vanish identically.
Abstract: An extended period numerical integration of a baroclinic primitive equation model has been made for the simulation and the study of the dynamics of the atmosphere's general circulation. The solution corresponding to external gravitational propagation is filtered by requiring the vertically integrated divergence to vanish identically. The vertical structure permits as dependent variables the horizontal wind at two internal levels and a single temperature, with the static stability entering as a parameter. The incoming radiation is a function of latitude only corresponding to the annual mean, and the outgoing radiation is taken to be a function of the local temperature. With the requirement for thermal equilibrium, the domain mean temperature is specified as a parameter. The role of condensation is taken into account only as it effectively reduces the static stability. All other external sources and sinks of heat are assumed to balance each other locally, and are thus omitted. The kinematics are th...
12,952 citations
Book•
01 Oct 2013TL;DR: In this paper, the fundamental physical processes involved in bubble dynamics and the phenomenon of cavitation are described and explained, and a review of the free streamline methods used to treat separated cavity flows with large attached cavities is provided.
Abstract: This book describes and explains the fundamental physical processes involved in bubble dynamics and the phenomenon of cavitation. It is intended as a combination of a reference book for those scientists and engineers who work with cavitation or bubble dynamics and as a monograph for advanced students interested in some of the basic problems associated with this category of multiphase flows. A basic knowledge of fluid flow and heat transfer is assumed but otherwise the analytical methods presented are developed from basic principles.
The book begins with a chapter on nucleation and describes both the theory and observations of nucleation in flowing and non-flowing systems. The following three chapters provide a systematic treatment of the dynamics of the growth, collapse or oscillation of individual bubbles in otherwise quiescent liquids. Chapter 4 summarizes the state of knowledge of the motion of bubbles in liquids. Chapter 5 describes some of the phenomena which occur in homogeneous bubbly flows with particular emphasis on cloud cavitation and this is followed by a chapter summarizing some of the experiemntal observations of cavitating flows. The last chapter provides a review of the free streamline methods used to treat separated cavity flows with large attached cavities.
2,994 citations
TL;DR: In this paper, a subgrid scale model is proposed for large eddy simulations in complex geometries, which accounts for the effects of both the strain and the rotation rate of the smallest resolved turbulent fluctuations.
Abstract: A new subgrid scale model is proposed for Large Eddy Simulations in complex geometries. This model which is based on the square of the velocity gradient tensor accounts for the effects of both the strain and the rotation rate of the smallest resolved turbulent fluctuations. Moreover it recovers the proper y
3 near-wall scaling for the eddy viscosity without requiring dynamic procedure. It is also shown from a periodic turbulent pipe flow computation that the model can handle transition.
2,855 citations
01 Jan 1989
TL;DR: Cell-centered and mesh-vertex upwind finite-volume schemes are developed which utilize multi-dimensional monotone linear reconstruction procedures which differ from existing algorithms (even on structured meshes).
Abstract: Solution and mesh generation algorithms for solving the Euler equations on unstructured meshes consisting of triangle and quadrilateral control volumes are presented. Cell-centered and mesh-vertex upwind finite-volume schemes are developed which utilize multi-dimensional monotone linear reconstruction procedures. These algorithms differ from existing algorithms (even on structured meshes). Numerical results in two dimensions are presented.
2,179 citations