Validation of a computer code for the simulation of turbulent flows past wings

2002 ◽

Author(s):

Horacio Antonio Flo´rez Guzma´n

Keyword(s):

Turbulent Flows ◽

Molecular Diffusion ◽

Numerical Study ◽

Computer Code ◽

Finite Difference Schemes ◽

Entire Volume ◽

Two Fluids ◽

Mass Dispersion ◽

Miscible Fluid ◽

Domain Discretization

A computer code for solving the equations of mass diffusion has been developed and applied to study the molecular-level mixing between two fluids inside a pipe. First, one fluid occupies the entire volume within the pipe, and then a second miscible fluid is forced into the pipe, developing a mixing process through the interface between the fluids. This phenomenon occurs as the combination of molecular diffusion, variation of velocity over the cross-section and turbulence. The code developed for this study is based on the finite element method for domain discretization and standard finite difference schemes for temporal discretization. Comparison with experimental data shows that the code is able to reproduce the physical trends and gives good predictions for engineering applications. A grid independence analysis is presented for all computations.

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Computational Fluid Dynamics Analysis of Turbulent Flow Within a Mechanical Seal Chamber

Journal of Tribology ◽

10.1115/1.2401220 ◽

2006 ◽

Vol 129 (1) ◽

pp. 120-128 ◽

Cited By ~ 12

Author(s):

Zhaogao Luan ◽

M. M. Khonsari

Keyword(s):

Reynolds Number ◽

Turbulent Flow ◽

Turbulent Flows ◽

High Reynolds Number ◽

Computer Code ◽

Computational Fluid Dynamics Analysis ◽

Significant Difference ◽

Approach Method ◽

High Reynolds ◽

Seal Chamber

Turbulent flow inside the seal chamber of a pump operating at high Reynolds number is investigated. The K−ε turbulence model posed in cylindrical coordinates was applied for this purpose. Simulations are performed using the fractional approach method. The results of the computer code are verified by using the FLUENT and by comparing to published results for turbulent Taylor Couette flow. Numerical results of four cases including two rotational speeds with four flush rates are reported. Significant difference between the laminar and the turbulence flow in the seal chamber is predicted. The behavior of the turbulent flows with very high Reynolds number was also investigated. The physical and practical implications of the results are discussed.

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A modified k - ε model of turbulence

Journal of Mechanical Engineering ◽

10.3329/jme.v38i0.895 ◽

1970 ◽

Vol 38 ◽

pp. 14-17 ◽

Cited By ~ 1

Author(s):

Showkat Jahan Chowdhury

Keyword(s):

Experimental Data ◽

Turbulent Flow ◽

Turbulent Flows ◽

Mechanical Engineering ◽

Computer Code ◽

Computational Results ◽

Consistent Model ◽

Model Predictions ◽

Computational Code ◽

Flow Through

In this paper, the parameters of a thermodynamically consistent k - ε model of turbulence are first determined, and the numerical values of the various model coefficients are evaluated. Limiting flows of a decaying homogeneous turbulence, turbulent flow in the inertial sublayer, and known properties of purely diffusive turbulence are used for this purpose. The thermodynamically consistent model is then incorporated into an enhanced version of the TEACH computer code called STARPIC. Finally, the modified computational code is used to simulate the flow through a channel to assess its capability in predicting turbulent flows. The computational results are compared with available experimental data, and found to have reasonable matching. The flows are also simulated using standard k - ε model, for comparison. It is observed that the present thermodynamically consistent modified k - ε model predictions are better compared to the standard k - ε model predictions.DOI: 10.3329/jme.v38i0.895 Journal of Mechanical Engineering Vol.38 Dec. 2007 pp.14-17

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Parallel Computation of Turbulent Flows Using Equation Decomposition Scheme

Journal of Mechanics ◽

10.1017/s1727719100000162 ◽

1998 ◽

Vol 14 (3) ◽

pp. 137-144 ◽

Cited By ~ 1

Author(s):

Shenq-Yuh Jaw ◽

Alpha Y. Wang

Keyword(s):

Parallel Computation ◽

Turbulent Flows ◽

Parallel Machines ◽

Stokes Equations ◽

Turbulent Channel Flow ◽

Computer Code ◽

Convergence Time ◽

Time Step ◽

Unit Process ◽

Decomposition Scheme

ABSTRACTA problem independent, equation decomposition scheme of parallel computation is adopted and tested using a two-dimensional turbulent channel flow. The incompressible Navier-Stokes equations, incorporated with the SIMPLEC algorithm and a two-layer turbulence model, were distributed to four nodes of IBM SP2 parallel machine using the PVM software and solved simultaneously. The computation domain and the interior iteration loop for the solution of every transport equation is the same, load balancing among different machines is automatically satisfied. Since all the transport equations and the flow field was solved and updated simultaneously, the solutions obtained from the equation decomposition scheme at each time step were more accurate than those obtained from a unit process code, which in turn sharply reduced the required convergence time steps. Without modifying any of the solution algorithm, or tuning the computer code, the rate of convergence speeds up more than four times by invoking four nodes of parallel machines using the equation decomposition scheme.

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A Numerical Study of Laminar and Intermittently Turbulent Flow Over a Flat Plate Using Pseudo-Compressibility Model

ASME 2019 Verification and Validation Symposium ◽

10.1115/vvs2019-5157 ◽

2019 ◽

Author(s):

S. Srivastava ◽

J. R. Eastridge ◽

B. M. Taravella ◽

K. M. Akyuzlu

Keyword(s):

Boundary Layer ◽

Finite Difference ◽

Turbulent Flow ◽

Flat Plate ◽

Turbulent Flows ◽

Numerical Study ◽

Computer Code ◽

Second Order ◽

Boundary Layer Equations ◽

Grid Convergence Index

Abstract A study was conducted to investigate the characteristics of incompressible unsteady boundary layer flows (laminar and intermittently turbulent), numerically and experimentally. The main objective of the study is to validate and verify (V&V) the accuracy of the proposed pseudo-compressibility model in solving the incompressible Navier-Stokes (NS) equations. This approach will enable one to use a second order accurate (temporally and spatially) implicit finite-difference (FD) technique to solve NS equations (including RANS equations). Here, the proposed pseudo-compressibility model is used for laminar and intermittent turbulent flow simulations. Flow over a flat plate is chosen as the benchmark case for the validation of the proposed pseudo-compressibility model. An in-house code is developed to solve the boundary layer equations using an Alternating-Direction Explicit (ADE) FD technique. The boundary layer equations are discretized using explicit FD techniques which are second order accurate. The velocity field predicted by this code is compared to the one given by Blasius’ analytical solution. A second in-house code is also developed which adopts the proposed model of pseudo-compressibility to solve the incompressible NS equations. The two dimensional, unsteady conservation of mass and momentum equations are discretized using explicit finite-difference techniques. A standard K-ε closure model is used along with RANS equation to simulate turbulent flows. The primitive variables (velocity and pressure) predicted by this code are compared to the ones predicted by a commercial CFD package (Fluent). Once the method of pseudo-compressibility is validated, it is then implemented into another in-house computer code which employs implicit FD technique and Coupled Modified Strongly Implicit Procedure (CMSIP) to solve for the unknowns of the problem under study. The predictions based on the pseudo-compressibility model for laminar flow are validated using the results of the experiments in which Particle Image Velocimetry (PIV) technique was employed. The verification; that is, the numerical uncertainty estimation of the pseudo-compressible code was accomplished by using the Grid Convergence Index (GCI) method. The results of the present study indicate that the proposed pseudo-compressibility model is capable of predicting experimentally observed characteristics of the external flows successfully, and deviations between the predicted velocity magnitudes and experimentally measured velocities are within an acceptable range for laminar and intermittently turbulent flows conditions.

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Numerical Solution of Three-Dimensional Turbulent Flows for Modern Gas Turbine Components

Volume 1: Turbomachinery ◽

10.1115/87-gt-84 ◽

1987 ◽

Cited By ~ 2

Author(s):

C. Hah ◽

J. H. Leylek

Keyword(s):

Gas Turbine ◽

Turbulent Flows ◽

Gas Turbines ◽

Solid Wall ◽

Control Volume ◽

Three Dimensional ◽

Computer Code ◽

Navier Stokes ◽

Navier Stokes Equation ◽

Aerodynamic Loss

This paper describes the development and assessment of a computer code for three-dimensional compressible turbulent flows in modern gas turbine components. The code is based on a high-order upwinding relaxation scheme with fully conservative control volume. A three-dimensional Reynolds-averaged Navier-Stokes equation is solved with a two-equation turbulence model that has a low Reynolds number modification near the solid wall. The code is applied to the study of compressible flow inside turbine blade rows of modern gas turbines. Measured data and calculations are carefully compared for the production and convection of aerodynamic loss to evaluate the code as an advanced design technique. The predicted aerodynamic performance is further compared with predictions based on current design techniques.

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Understanding the Effect of Trenching on Film Cooling

ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference, Volume 3 ◽

10.1115/ht2007-32598 ◽

2007 ◽

Cited By ~ 2

Author(s):

Yiping Lu ◽

Srinath V. Ekkad

Keyword(s):

Experimental Data ◽

Turbulent Flows ◽

Film Cooling ◽

Computer Code ◽

Two Dimensional ◽

Transport Models ◽

Strong Focus ◽

Two Dimensional Flow ◽

Cylindrical Holes ◽

Film Cooling Holes

Recently, there has been a strong focus on film cooling holes embedded in trenches. In this study, film cooling predictions are used to understand the mechanisms of the jets that exit these trenched holes. The present work employs RSM (Reynolds stress transport models) for simulation of turbulent flows in film cooling and the simulation was run using FLUENT computer code. Comparisons are made with experimental data for the film effectiveness distributions. Results show that the film cooling jet exiting the trenched hole shows more two-dimensional flow than the typical cylindrical holes. The jet appears to remain closer to the surface providing more coverage to the surface.

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The Computational Sublime in Nick Montfort's ‘Round’ and ‘All the Names of God’

CounterText ◽

10.3366/count.2015.0027 ◽

2015 ◽

Vol 1 (3) ◽

pp. 348-365 ◽

Cited By ~ 2

Author(s):

Mario Aquilina

Keyword(s):

Computer Code ◽

Computer Programs ◽

Literary Text ◽

Text Generation ◽

Mathematical Concepts ◽

Literary Space

What if the post-literary also meant that which operates in a literary space (almost) devoid of language as we know it: for instance, a space in which language simply frames the literary or poetic rather than ‘containing’ it? What if the countertextual also meant the (en)countering of literary text with non-textual elements, such as mathematical concepts, or with texts that we would not normally think of as literary, such as computer code? This article addresses these issues in relation to Nick Montfort's #!, a 2014 print collection of poems that presents readers with the output of computer programs as well as the programs themselves, which are designed to operate on principles of text generation regulated by specific constraints. More specifically, it focuses on two works in the collection, ‘Round’ and ‘All the Names of God’, which are read in relation to the notions of the ‘computational sublime’ and the ‘event’.

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