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Sanjoy Banerjee

Bio: Sanjoy Banerjee is an academic researcher from City College of New York. The author has contributed to research in topics: Turbulence & Two-phase flow. The author has an hindex of 52, co-authored 229 publications receiving 8880 citations. Previous affiliations of Sanjoy Banerjee include City University of New York & Atomic Energy of Canada Limited.


Papers
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Journal ArticleDOI
TL;DR: In this article, a semi-implicit discretization for the convective Cahn-Hilliard equation with high-resolution schemes employed for direct numerical simulations of turbulence is proposed.

512 citations

01 Nov 2002
TL;DR: An accurate and efficient numerical method to solve the coupled Cahn-Hilliard/Navier-Stokes system, known as Model H, that constitutes a phase field model for density-matched binary fluids with variable mobility and viscosity, and solves the Navier- Stokes equations with a robust time-discretization of the projection method that guarantees better stability properties than those for Crank-Nicolson-based projection methods.
Abstract: Phase field models offer a systematic physical approach for investigating complex multiphase systems behaviors such as near-critical interfacial phenomena, phase separation under shear, and microstructure evolution during solidification. However, because interfaces are replaced by thin transition regions (diffuse interfaces), phase field simulations require resolution of very thin layers to capture the physics of the problems studied. This demands robust numerical methods that can efficiently achieve high resolution and accuracy, especially in three dimensions. We present here an accurate and efficient numerical method to solve the coupled Cahn-Hilliard/Navier-Stokes system, known as Model H, that constitutes a phase field model for density-matched binary fluids with variable mobility and viscosity. The numerical method is a time-split scheme that combines a novel semi-implicit discretization for the convective Cahn-Hilliard equation with an innovative application of high-resolution schemes employed for direct numerical simulations of turbulence. This new semi-implicit discretization is simple but effective since it removes the stability constraint due to the nonlinearity of the Cahn-Hilliard equation at the same cost as that of an explicit scheme. It is derived from a discretization used for diffusive problems that we further enhance to efficiently solve flow problems with variable mobility and viscosity. Moreover, we solve the Navier-Stokes equations with a robust time-discretization of the projection method that guarantees better stability properties than those for Crank-Nicolson-based projection methods. For channel geometries, the method uses a spectral discretization in the streamwise and spanwise directions and a combination of spectral and high order compact finite difference discretizations in the wall normal direction. The capabilities of the method are demonstrated with several examples including phase separation with, and without, shear in two and three dimensions. The method effectively resolves interfacial layers of as few as three mesh points. The numerical examples show agreement with analytical solutions and scaling laws, where available, and the 3D simulations, in the presence of shear, reveal rich and complex structures, including strings.

456 citations

Journal ArticleDOI
TL;DR: A sharp interface capturing method is described for the study of incompressible multiphase flows with phase change using the level set method to keep track of the interface between the two phases and a ghost fluid approach to impose the jump conditions at the interface.

313 citations

Journal ArticleDOI
TL;DR: In this article, a series of experiments varying particle size, particle density, particle loading and flow Re has been conducted, and a mechanism of particle transport in wall turbulent flows has been proposed, in which the particles are transported by the bursting events of the wall regions.

283 citations

Journal ArticleDOI
TL;DR: In this article, the motion of solid particles near the wall in a turbulent boundary layer was investigated experimentally in a water flume by flow visualization techniques and by LDA, and the results showed that particle motion, as well as entrainment and deposition processes, are controlled by the action of coherent wall structures, which appear to be funnel vortices.
Abstract: The motion of solid particles near the wall in a turbulent boundary layer was investigated experimentally in a water flume by flow visualization techniques and by LDA. The particles were of polystyrene (specific density ∼1.05) with diameters ranging from 100 to 900 μm. Results show that particle motion, as well as entrainment and deposition processes, are controlled by the action of coherent wall structures, which appear to be funnel vortices. The behavior of the particles is consistent with the motion and effects of such vortices. The vortices appear to cause the formation of particle streaks near the wall, to create suitable conditions for particle entrainment, and to assist in particle deposition by conveying them from the outer flow to the wall region.

278 citations


Cited by
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Book
31 Jan 2004
TL;DR: Part I Theoretical concepts: introduction suboptimal nonlinear filters a tutorial on particle filters Cramer-Rao bounds for nonlinear filtering and tracking applications: tracking a ballistic object bearings-only tracking range- only tracking bistatic radar tracking targets through blind Doppler terrain aided tracking detection and tracking of stealthy targets group and extended object tracking.
Abstract: Part I Theoretical concepts: introduction suboptimal nonlinear filters a tutorial on particle filters Cramer-Rao bounds for nonlinear filtering Part II Tracking applications: tracking a ballistic object bearings-only tracking range-only tracking bistatic radar tracking tracking targets through blind Doppler terrain aided tracking detection and tracking of stealthy targets group and extended object tracking

3,690 citations

Journal ArticleDOI
TL;DR: The atomic force microscope (AFM) is not only used to image the topography of solid surfaces at high resolution but also to measure force-versus-distance curves as discussed by the authors, which provide valuable information on local material properties such as elasticity, hardness, Hamaker constant, adhesion and surface charge densities.

3,281 citations

Journal ArticleDOI
TL;DR: To the best of our knowledge, there is only one application of mathematical modelling to face recognition as mentioned in this paper, and it is a face recognition problem that scarcely clamoured for attention before the computer age but, having surfaced, has attracted the attention of some fine minds.
Abstract: to be done in this area. Face recognition is a problem that scarcely clamoured for attention before the computer age but, having surfaced, has involved a wide range of techniques and has attracted the attention of some fine minds (David Mumford was a Fields Medallist in 1974). This singular application of mathematical modelling to a messy applied problem of obvious utility and importance but with no unique solution is a pretty one to share with students: perhaps, returning to the source of our opening quotation, we may invert Duncan's earlier observation, 'There is an art to find the mind's construction in the face!'.

3,015 citations

Book
01 Oct 2013
TL;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

Book ChapterDOI
01 Jan 1997
TL;DR: The boundary layer equations for plane, incompressible, and steady flow are described in this paper, where the boundary layer equation for plane incompressibility is defined in terms of boundary layers.
Abstract: The boundary layer equations for plane, incompressible, and steady flow are $$\matrix{ {u{{\partial u} \over {\partial x}} + v{{\partial u} \over {\partial y}} = - {1 \over \varrho }{{\partial p} \over {\partial x}} + v{{{\partial ^2}u} \over {\partial {y^2}}},} \cr {0 = {{\partial p} \over {\partial y}},} \cr {{{\partial u} \over {\partial x}} + {{\partial v} \over {\partial y}} = 0.} \cr }$$

2,598 citations