scholarly journals Simulation of Oldroyd-B Viscoelastic Fluid in Axisymmetric Straight Channel by Using a Hybrid Finite Element/Volume Method

2021 ◽  
Vol 81 (1) ◽  
pp. 26-40
Author(s):  
Ihssan Aqeel Fadhel ◽  
Alaa Hassan Al-Muslimawi
Keyword(s):  
Finite Element ◽  
Stress Response ◽  
Finite Volume ◽  
Viscoelastic Fluid ◽  
Circular Channel ◽  
System Solution ◽  
Stress Components ◽  
Volume Method ◽  
Solvent Fraction ◽  
Element Method

In this study, incompressible viscoelastic fluid through the axisymmetric circular channel is simulated with Oldroyd-B model. The simulation is performed based on a hybrid finite volume/element method, which consists of Taylor-Galerkin finite element discretisation, and a cell vertex fluctuation-distribution finite volume method. In this context, the momentum and continuity equations are treated with a finite element method, while a finite volume approach is applied to solve the Oldroyd-B constitutive model. Analytical expressions are presented for the velocity and stress components in fully developed channel flow of Oldroyd-B fluid. For this complex fluid, we see an excellent agreement between the analytic and the numerical solutions. The study of axisymmetric circular channel problem based on a hybrid numerical method represents a great challenge. The novelty here is to study the temporal convergence-rate of the system solution that is taken to be steady state, incompressible, axisymmetric, and laminar, which did not address by researchers previously. Here, the rate of convergence for all solution components is presented, where a large level of convergence is appeared for stress compared to the other solution components. Moreover, the pressure drops and stress response across the flow are provided with respect to difference in solvent-fraction and Weissenberg number . A significant effect from the viscoelastic parameters upon the level of the stress has been detected, while for the pressure response the change is semi-modest. For the stress response the findings reveal that, with decreasing solvent-fraction , the maxima level of stress components are strongly amplifies.

Dynamic Response of Underwater Structures Subject to Impact Loads

2011 ◽  
Author(s):  
Lingyu Sun ◽  
Weiwei Chen ◽  
Xiaojie Wang ◽  
Ning Kang ◽  
Bin Xu ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Response ◽  
Finite Volume Method ◽  
Finite Volume ◽  
Impact Loads ◽  
Main Body ◽  
Energy Absorber ◽  
Volume Method ◽  
Element Method

The present paper studied the dynamic response of an underwater system with its navigation plate rotated relative to the main body until it was blocked by an energy absorber. In this process, the relation between fluid-driving moment and speed of main body, as well as the relation between rotation angle of the plate and design parameters of absorber, was investigated through combined finite element method and finite volume method. Before the plate contacted with the energy absorber, it was modeled by linear elastic material, the movement process was solved by finite volume method with dynamic boundary. When the plate started to contact and crash with the absorber, it was modeled by elastic-plastic material, and the interaction of fluid-structure coupling was simulated by explicit finite element method in LSDYNA and finite volume method in FLUENT. The two-way data exchange on the interface between fluid and structure was carried out through equivalent force and moment on each patch of the interface. In addition, the simulation accuracy on large plastic deformation of absorber was verified through a group of drop hammer experiments. After the energy absorber was crushed to ultimate shape, the open angle of plate reached the maximum value and the plate kept relative static to the rigid body. The maximum structural stress and deformation, the opening time and angle of the plate were evaluated by numerical method. It is demonstrated that the proposed method can effectively predict the dynamic response of underwater system under impact loads, and both the absorption capability of the block and the speed of moving body affect the dynamic response history and structural safety.

Numerical Solution of Multidimensional Compressible Flow by High Order Nodal Discontinuous Galerkin Method

2013 ◽  
Vol 392 ◽  
pp. 100-104 ◽  
Author(s):  
Fareed Ahmed ◽  
Faheem Ahmed ◽  
Yong Yang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Solution ◽  
Finite Volume Method ◽  
Discontinuous Galerkin ◽  
Finite Volume ◽  
High Order ◽  
Numerical Predictions ◽  
Volume Method ◽  
Element Method

In this paper we present a robust, high order method for numerical solution of multidimensional compressible inviscid flow equations. Our scheme is based on Nodal Discontinuous Galerkin Finite Element Method (NDG-FEM). This method utilizes the favorable features of Finite Volume Method (FVM) and Finite Element Method (FEM). In this method, space discretization is carried out by finite element discontinuous approximations. The resulting semi discrete differential equations were solved using explicit Runge-Kutta (ERK) method. In order to compute fluxes at element interfaces, we have used Roe Approximate scheme. In this article, we demonstrate the use of exponential filter to remove Gibbs oscillations near the shock waves. Numerical predictions for two dimensional compressible fluid flows are presented here. The solution was obtained with overall order of accuracy of 3. The numerical results obtained are compared with experimental and finite volume method results.

scholarly journals Code-to-code verification for thermal models of melting and solidification in a metal alloy: comparisons between a Finite Volume Method and a Finite Element Method

2020 ◽  
Vol 11 (1) ◽  
pp. 125-135
Author(s):  
Anna M. V. Harley ◽  
Sagar H. Nikam ◽  
Hao Wu ◽  
Justin Quinn ◽  
Shaun McFadden
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Volume Method ◽  
Finite Volume ◽  
Manufacturing Processes ◽  
Code Verification ◽  
Thermal Models ◽  
Volume Method ◽  
Melting And Solidification ◽  
Element Method

Abstract. Verification, the process of checking a modelling output against a known reference model, is an important step in model development for the simulation of manufacturing processes. This manuscript provides details of a code-to-code verification between two thermal models used for simulating the melting and solidification processes in a 316 L stainless steel alloy: one model was developed using a non-commercial code and the Finite Volume Method (FVM) and the other used a commercial Finite Element Method (FEM) code available within COMSOL Multiphysics®. The application involved the transient case of heat-transfer from a point heat source into one end of a cylindrical sample geometry, thus melting and then re-solidifying the sample in a way similar to an autogenous welding process in metal fabrication. Temperature dependent material properties and progressive latent heat evolution through the freezing range of the alloy were included in the model. Both models were tested for mesh independency, permitting meaningful comparisons between thermal histories, temperature profiles and maximum temperature along the length of the cylindrical rod and melt pool depth. Acceptable agreement between the results obtained by the non-commercial and commercial models was achieved. This confidence building step will allow for further development of point-source heat models, which has a wide variety of applications in manufacturing processes.

Error analysis of finite element and finite volume methods for some viscoelastic fluids

2016 ◽  
Vol 24 (2) ◽  
Author(s):  
Mária Lukáčová-Medvid’ová ◽  
Hana Mizerová ◽  
Bangwei She ◽  
Jan Stebel
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Error Analysis ◽  
Finite Volume ◽  
Finite Volume Methods ◽  
Weissenberg Number ◽  
Type Model ◽  
The Finite Element Method ◽  
Volume Method ◽  
Element Method

AbstractWe present the error analysis of a particular Oldroyd-B type model with the limiting Weissenberg number going to infinity. Assuming a suitable regularity of the exact solution we study the error estimates of a standard finite element method and of a combined finite element/finite volume method. Our theoretical result shows first order convergence of the finite element method and the error of the order 𝓞(

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