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An investigation of the film thickness calculation for
Finite element simulation of three-dimensional free-surface flow problems
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Scientific research is often multidisciplinary in nature and hence large projects are frequently collaborative with participants from several separate research centres. Rather than being restricted to infrequent dissemination of results... more
Scientific research is often multidisciplinary in nature and hence large projects are frequently collaborative with participants from several separate research centres. Rather than being restricted to infrequent dissemination of results and meetings a framework is described for embedding scientific computing applications within a collaborative problem solving environment. This allows users to combine their expertise in an interactive visual environment. Separate users can collaboratively steer and visualize data from a numerical simulation by embedding the simulation within the IRIS Explorer visualization system. By making use of this system the user has access to the COVISA toolkit which facilitates collaboration between separate users of IRIS Explorer. The exibility of this system makes it straightforward to visualize and control as many aspects of the solution process as are desired.
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In this article, we present a new unified finite element method (UFEM) for simulation of general Fluid-Structure interaction (FSI) which has the same generality and robustness as monolithic methods but is significantly more... more
In this article, we present a new unified finite element method (UFEM) for simulation of general Fluid-Structure interaction (FSI) which has the same generality and robustness as monolithic methods but is significantly more computationally efficient and easier to implement. Our proposed approach has similarities with classical immersed finite element methods (IFEMs), by approximating a single velocity and pressure field in the entire domain (i.e. occupied by fluid and solid) on a single mesh, but differs by treating the corrections due to the solid deformation on the left-hand side of the modified fluid flow equations (i.e. implicitly). The method is described in detail, followed by the presentation of multiple computational examples in order to validate it across a wide range of fluid and solid parameters and interactions.
In this article, we derive an adjoint fluid-structure interaction (FSI) system in an arbitrary Lagrangian-Eulerian (ALE) framework, based upon a one-field finite element method. A key feature of this approach is that the interface... more
In this article, we derive an adjoint fluid-structure interaction (FSI) system in an arbitrary Lagrangian-Eulerian (ALE) framework, based upon a one-field finite element method. A key feature of this approach is that the interface condition is automatically satisfied and the problem size is reduced since we only solve for one velocity field for both the primary and adjoint system. A velocity (and/or displacement)-matching optimisation problem is considered by controlling a distributed force. The optimisation problem is solved using a gradient descent method, and a stabilised Barzilai-Borwein method is adopted to accelerate the convergence, which does not need additional evaluations of the objective functional. The proposed control method is validated and assessed against a series of static and dynamic benchmark FSI problems, before being applied successfully to solve a highly challenging FSI control problem.
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SUMMARY Two algorithms for solving the elastohydrodynamic lubrication problem are compared in this paper. The first, a so-called decoupled method, employs an integral form for the calculation of the elastic deformation of the solid... more
SUMMARY Two algorithms for solving the elastohydrodynamic lubrication problem are compared in this paper. The first, a so-called decoupled method, employs an integral form for the calculation of the elastic deformation of the solid surfaces (1). The second, a coupled method, uses either the integral form or a reformulation of the deflection computation into an equivalent differential form (2). Results
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SUMMARY Two algorithms for solving the elastohydrodynamic lubrication problem are compared in this paper. The first, a so-called decoupled method, employs an integral form for the calculation of the elastic deformation of the solid... more
SUMMARY Two algorithms for solving the elastohydrodynamic lubrication problem are compared in this paper. The first, a so-called decoupled method, employs an integral form for the calculation of the elastic deformation of the solid surfaces (1). The second, a coupled method, uses either the integral form or a reformulation of the deflection computation into an equivalent differential form (2). Results are presented which contrast the accuracy of the two approaches and consider their efficient numerical implementation. Copyright c 2007 John Wiley & Sons, Ltd.
We present an overview of a recently-developed finite element software tool for the simulation of non-Newtonian fluid flows arising in viscoelastic polymer melts. The software is based upon the use of quantitative macroscopic constitutive... more
We present an overview of a recently-developed finite element software tool for the simulation of non-Newtonian fluid flows arising in viscoelastic polymer melts. The software is based upon the use of quantitative macroscopic constitutive laws, defining the evolution of polymer stress, which contributes to the total fluid stress in the flow. A wide range of melt rheologies may be considered in this manner, and three specific examples are considered in this paper. In addition to providing a detailed overview of the software, a number of sample numerical simulations are presented to illustrate the capabilities of the code.
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This paper presents a new numerical method to solve transient line contact elastohydrodynamic lubrication (EHL) problems. A high-order Discontinuous Galerkin nite element method is used for the spatial discretization and the stan- dard... more
This paper presents a new numerical method to solve transient line contact elastohydrodynamic lubrication (EHL) problems. A high-order Discontinuous Galerkin nite element method is used for the spatial discretization and the stan- dard Crank-Nicolson method is employed to approximate the time derivative. An h-adaptivity method is used for grid adaptation with the time-stepping and the penalty method is employed to
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Abstract. Scientific research is often multidisciplinary in nature and hence large projects are frequently collaborative with participants from several separate research centres. Rather than being restricted to infre-quent dissemination... more
Abstract. Scientific research is often multidisciplinary in nature and hence large projects are frequently collaborative with participants from several separate research centres. Rather than being restricted to infre-quent dissemination of results and meetings a framework is described for ...
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Abstract Vascular surgery is a technically demanding surgical speciality, one component of which is the accurate placement of sutures through a diseased vessel wall. Minor errors can result in thrombosis and failure of the procedure. To... more
Abstract Vascular surgery is a technically demanding surgical speciality, one component of which is the accurate placement of sutures through a diseased vessel wall. Minor errors can result in thrombosis and failure of the procedure. To develop the necessary skills takes ...
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An arbitrary Lagrangian-Eulerian finite element method is de- scribed for the solution of time-dependent, three-dimensional, free- surface flow problems. Many flows of practical significance involve contact lines, where the free surface... more
An arbitrary Lagrangian-Eulerian finite element method is de- scribed for the solution of time-dependent, three-dimensional, free- surface flow problems. Many flows of practical significance involve contact lines, where the free surface meets a solid boundary. This con- tact line may be pinned to a particular part of the solid but is more typically free to slide in a manner that is characterised by the dynamic contact angle formed by the fluid. We focus on the latter case and use a model that admits spatial variation of the contact angle: thus
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SUMMARY An arbitrary Lagrangian-Eulerian (ALE) finite element method is described for the solution of three-dimensional free-surface flow problems. The focus of this work is on extending the algorithm to include a dynamic contact line... more
SUMMARY An arbitrary Lagrangian-Eulerian (ALE) finite element method is described for the solution of three-dimensional free-surface flow problems. The focus of this work is on extending the algorithm to include a dynamic contact line model allowing the fluid free surface, in the steady case, to form a prespecified static contact angle with a solid boundary and, in the transient case,