scholarly journals Evaluating the Capability of the Flux-Limiter Schemes in Capturing Strong Shocks and Discontinuities

2013 ◽  
Vol 20 (2) ◽  
pp. 287-296 ◽  
Author(s):  
Iman Harimi ◽  
Ahmad Reza Pishevar
Keyword(s):  
Numerical Study ◽  
Wave Interaction ◽  
Numerical Code ◽  
Test Problems ◽  
Governing Equations ◽  
Tvd Schemes ◽  
One Dimensional ◽  
Flux Limiter ◽  
Acoustic Interaction ◽  
Density Disturbance

A numerical study is conducted to investigate the capability of the flux-limiter TVD schemes in capturing sharp discontinuities like shock waves. For this purpose, four classical test problems are considered such as slowly moving shock, gas Riemann problem with high density and pressure ratios, shock wave interaction with a density disturbance and shock-acoustic interaction. The governing equations consist of one-dimensional and quasi-one-dimensional Euler equations solved using an in-house numerical code. In order to validate the solution, the obtained results are compared with other results found in the literature.

scholarly journals A Numerical Approach to Solve Volume-Based Batch Crystallization Model with Fines Dissolution Unit

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 453 ◽  
Author(s):  
Mukhtar ◽  
Sohaib ◽  
Ahmad
Keyword(s):  
Numerical Approximation ◽  
Chemical Engineering ◽  
Numerical Study ◽  
Moment Generating Function ◽  
Numerical Approach ◽  
Test Problems ◽  
Batch Crystallization ◽  
One Dimensional ◽  
Engineering Sciences ◽  
The Moment

In this article, a numerical study of a one-dimensional, volume-based batch crystallization model (PBM) is presented that is used in numerous industries and chemical engineering sciences. A numerical approximation of the underlying model is discussed by using an alternative Quadrature Method of Moments (QMOM). Fines dissolution term is also incorporated in the governing equation for improvement of product quality and removal of undesirable particles. The moment-generating function is introduced in order to apply the QMOM. To find the quadrature abscissas, an orthogonal polynomial of degree three is derived. To verify the efficiency and accuracy of the proposed technique, two test problems are discussed. The numerical results obtained by the proposed scheme are plotted versus the analytical solutions. Thus, these findings line up well with the analytical findings.

scholarly journals Experimental and numerical study of submerged jets from pipes of different wall thickness for Re<1

2019 ◽  
Vol 66 (1) ◽  
pp. 69
Author(s):  
M. Sánchez-Rosas ◽  
J. Casillas-Navarrete ◽  
J.A. Jiménez-Bernal ◽  
V.N. Kurdyumov ◽  
A. Medina
Keyword(s):  
Wall Thickness ◽  
Numerical Study ◽  
Numerical Results ◽  
Numerical Code ◽  
Governing Equations ◽  
Pipe Wall Thickness ◽  
Submerged Jet ◽  
Piv Technique ◽  
Submerged Jets ◽  
Image Velocimetry

In this work, the experimental and numerical results from the study of the effects caused in a submerged jet flow by the change in the wall thickness of the circular tube from which said flow originates are presented. For small values of the Reynolds number Re (Re\approx0.11), four cases, regarding the ratio of pipe wall thickness to its radius, are considered: (I) pipe thickness is a fourth of the radius, (II) pipe thickness is a half the radius, (III) pipe thickness is equal to the radius and (IV) pipe thickness is three times the radius. The Particle Image Velocimetry (PIV) technique was used in order to obtain experimentally the velocity and streamlines distributions. A numerical code based on the finite difference method was developed to solve the motion governing equations and the numerical results were compared with the values obtained experimentally. 

One-dimensional numerical study of compressible flow ejector

AIAA Journal ◽  
2002 ◽  
Vol 40 ◽  
pp. 1469-1472
Author(s):  
S. Han ◽  
J. Peddieson
Keyword(s):  
Compressible Flow ◽  
Numerical Study ◽  
One Dimensional

Investigation of two-dimensional nonstationary processes of outflow a gas-saturated liquid from axisymmetric vessels

2012 ◽  
Vol 9 (1) ◽  
pp. 47-52
Author(s):  
R.Kh. Bolotnova ◽  
V.A. Buzina
Keyword(s):  
Comparative Analysis ◽  
Numerical Model ◽  
Liquid Mixture ◽  
Phase Model ◽  
Test Problems ◽  
Two Dimensional ◽  
Nonstationary Processes ◽  
Saturated Liquid ◽  
Two Phase ◽  
One Dimensional

The two-dimensional and two-phase model of the gas-liquid mixture is constructed. The validity of numerical model realization is justified by using a comparative analysis of test problems solution with one-dimensional calculations. The regularities of gas-saturated liquid outflow from axisymmetric vessels for different geometries are established.

scholarly journals Computational Evaluation of Shock Wave Interaction with a Cylindrical Water Column

2021 ◽  
Vol 11 (11) ◽  
pp. 4934
Author(s):  
Viola Rossano ◽  
Giuliano De Stefano
Keyword(s):  
Shock Wave ◽  
Water Column ◽  
Wave Interaction ◽  
Navier Stokes ◽  
Plane Shock ◽  
Governing Equations ◽  
Computational Evaluation ◽  
Air Water Interface ◽  
The Mean ◽  
The Impact

Computational fluid dynamics was employed to predict the early stages of the aerodynamic breakup of a cylindrical water column, due to the impact of a traveling plane shock wave. The unsteady Reynolds-averaged Navier–Stokes approach was used to simulate the mean turbulent flow in a virtual shock tube device. The compressible flow governing equations were solved by means of a finite volume-based numerical method, where the volume of fluid technique was employed to track the air–water interface on the fixed numerical mesh. The present computational modeling approach for industrial gas dynamics applications was verified by making a comparison with reference experimental and numerical results for the same flow configuration. The engineering analysis of the shock–column interaction was performed in the shear-stripping regime, where an acceptably accurate prediction of the interface deformation was achieved. Both column flattening and sheet shearing at the column equator were correctly reproduced, along with the water body drift.

scholarly journals A 3DEC Numerical Analysis of the Interaction Between an Uneven Rock Surface and Shotcrete Lining

2021 ◽  
Author(s):  
Ping Zhang ◽  
Ering Nordlund
Keyword(s):  
Numerical Study ◽  
Support Effect ◽  
Influential Factors ◽  
Numerical Analyses ◽  
Numerical Code ◽  
Rock Surface ◽  
Stress Concentrations ◽  
Circular Tunnel ◽  
Rock Tunnels ◽  
Shotcrete Lining

AbstractRock tunnels excavated using drilling and blasting technique in jointed rock masses often have a very uneven and rough excavation surface. Experience from previous studies shows that the unevenness of a rock surface has a large impact on the support effect of shotcrete lining. However, clear conclusions regarding the effect of 2D and 3D uneven surfaces were not obtained due to limited studies in the literature. The numerical analyses reported in this paper were made to investigate the influence of the surface unevenness of a circular tunnel opening on the support effect of shotcrete using a 3D numerical code (3DEC). The models were first calibrated with the help of observations and measured data obtained from physical model tests. The influential factors were investigated further in this numerical study after calibration had been achieved. The numerical analyses show that, in general, the unevenness of a tunnel surface produces negative support effects due to stress concentrations in recesses (compressive) and at apexes (tensile) after excavation. However, shotcrete sprayed on a doubly waved uneven surface has better support effect compared to shotcrete sprayed on a simply waved tunnel surface. The development of shear strength (specifically frictional strength) on the uneven interface between the shotcrete and the rock contributes to this effect, in the condition where bonding of the shotcrete does not work effectively. The interface is a crucial element when the interaction between the rock and shotcrete is to be simulated. When an entire tunnel surface is covered by shotcrete with high modulus, more failures will occur in the shotcrete especially when rock surface is uneven. Based on the numerical model cases examined, some recommendations on how to incorporate tunnel surface conditions (2D or 3D unevenness) in the design of a shotcrete lining are given.

Numerical Study of Wave Slamming on a Rectangular Slab

2012 ◽  
Vol 204-208 ◽  
pp. 4971-4977
Author(s):  
Ya Mei Lan ◽  
Wen Hua Guo ◽  
Yong Guo Li
Keyword(s):  
Numerical Study ◽  
Navier Stokes ◽  
Governing Equations ◽  
Reflected Waves ◽  
Rans Equations ◽  
Numerical Wave Flume ◽  
Wave Flume ◽  
Wave Slamming ◽  
Numerical Wave ◽  
Rectangular Slab

The CFD software FLUENT was used as the foundation to develop the numerical wave flume, in which the governing equations are the Reynolds-averaged Navier-Stokes (RANS) equations and the standard k~ε turbulence model. The wave generating and absorbing were introduced into the RANS equations as the source terms using the relaxation approach. A new module of the wave generating and absorbing function, which is suitable for FLUENT based on the volume of fluid method (VOF), was established. Within the numerical wave flume, the reflected waves from the model within the computation domain can be absorbed effectively before second reflection appears due to the wave generating boundary. The computational results of the wave pressures on the bottom of the rectangular slab were validated for the different relative clearance by the experimental data. Good agreements were found.

scholarly journals Numerical Modeling of the Interaction of Solitary Waves and Submerged Breakwaters with Sharp Vertical Edges Using One-Dimensional Beji & Nadaoka Extended Boussinesq Equations

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Mohammad H. Jabbari ◽  
Parviz Ghadimi ◽  
Ali Masoudi ◽  
Mohammad R. Baradaran
Keyword(s):  
Solitary Waves ◽  
Numerical Study ◽  
Time Integration ◽  
Boussinesq Equations ◽  
Linear Interpolation ◽  
Reflected Waves ◽  
One Dimensional ◽  
Propagating Waves ◽  
Linear Elements ◽  
Predictor Corrector

Using one-dimensional Beji & Nadaoka extended Boussinesq equation, a numerical study of solitary waves over submerged breakwaters has been conducted. Two different obstacles of rectangular as well as circular geometries over the seabed inside a channel have been considered in view of solitary waves passing by. Since these bars possess sharp vertical edges, they cannot directly be modeled by Boussinesq equations. Thus, sharply sloped lines over a short span have replaced the vertical sides, and the interactions of waves including reflection, transmission, and dispersion over the seabed with circular and rectangular shapes during the propagation have been investigated. In this numerical simulation, finite element scheme has been used for spatial discretization. Linear elements along with linear interpolation functions have been utilized for velocity components and the water surface elevation. For time integration, a fourth-order Adams-Bashforth-Moulton predictor-corrector method has been applied. Results indicate that neglecting the vertical edges and ignoring the vortex shedding would have minimal effect on the propagating waves and reflected waves with weak nonlinearity.

Design and Research of Flat Micro Heat Pipe with Glass Fiber Wick

2011 ◽  
Vol 483 ◽  
pp. 603-606
Author(s):  
Tian Han ◽  
Xiao Wei Liu ◽  
Chao Wang
Keyword(s):  
Glass Fiber ◽  
Heat Pipe ◽  
Experimental Testing ◽  
Governing Equations ◽  
Maximum Heat ◽  
One Dimensional ◽  
Micro Heat Pipe ◽  
Wick Structure

A kind of flat micro heat pipe with glass fiber wick structure is designed and fabricated. The structure of the wick is presented and also the excellence of the structure is described. For the glass fiber wick, the maximum heat transports is calculated by one-dimensional steady governing equations. Experimental testing is performed for the fabricated micro heat pipe in vacuum. The testing results is presented and analyzed.

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