Experimental Methodology for Computational Fluid Dynamics Code Validation

Experimental Methodology for Computational Fluid Dynamics Code Validation PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 35

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Book Description
Validation of Computational Fluid Dynamics (CFD) codes is an essential element of the code development process. Typically, CFD code validation is accomplished through comparison of computed results to previously published experimental data that were obtained for some other purpose, unrelated to code validation. As a result, it is a near certainty that not all of the information required by the code, particularly the boundary conditions, will be available. The common approach is therefore unsatisfactory, and a different method is required. This paper describes a methodology developed specifically for experimental validation of CFD codes. The methodology requires teamwork and cooperation between code developers and experimentalists throughout the validation process, and takes advantage of certain synergisms between CFD and experiment. The methodology employs a novel uncertainty analysis technique which helps to define the experimental plan for code validation wind tunnel experiments, and to distinguish between and quantify various types of experimental error. The methodology is demonstrated with an example of surface pressure measurements over a model of varying geometrical complexity in laminar, hypersonic, near perfect gas, 3-dimensional flow.

Experimental Methodology for Computational Fluid Dynamics Code Validation

Experimental Methodology for Computational Fluid Dynamics Code Validation PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 35

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Book Description
Validation of Computational Fluid Dynamics (CFD) codes is an essential element of the code development process. Typically, CFD code validation is accomplished through comparison of computed results to previously published experimental data that were obtained for some other purpose, unrelated to code validation. As a result, it is a near certainty that not all of the information required by the code, particularly the boundary conditions, will be available. The common approach is therefore unsatisfactory, and a different method is required. This paper describes a methodology developed specifically for experimental validation of CFD codes. The methodology requires teamwork and cooperation between code developers and experimentalists throughout the validation process, and takes advantage of certain synergisms between CFD and experiment. The methodology employs a novel uncertainty analysis technique which helps to define the experimental plan for code validation wind tunnel experiments, and to distinguish between and quantify various types of experimental error. The methodology is demonstrated with an example of surface pressure measurements over a model of varying geometrical complexity in laminar, hypersonic, near perfect gas, 3-dimensional flow.

A Proposed Methodology for Computational Fluid Dynamics Code Verification, Calibration, and Validation

A Proposed Methodology for Computational Fluid Dynamics Code Verification, Calibration, and Validation PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 14

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Book Description
Verification, calibration, and validation (VCV) of Computational Fluid Dynamics (CFD) codes is an essential element of the code development process. The exact manner in which code VCV activities are planned and conducted, however, is critically important. It is suggested that the way in which code validation, in particular, is often conducted--by comparison to published experimental data obtained for other purposes--is in general difficult and unsatisfactory, and that a different approach is required. This paper describes a proposed methodology for CFD code VCV that meets the technical requirements and is philosophically consistent with code development needs. The proposed methodology stresses teamwork and cooperation between code developers and experimentalists throughout the VCV process, and takes advantage of certain synergisms between CFD and experiment. A novel approach to uncertainty analysis is described which can both distinguish between and quantify various types of experimental error, and whose attributes are used to help define an appropriate experimental design for code VCV experiments. The methodology is demonstrated with an example of laminar, hypersonic, near perfect gas, 3-dimensional flow over a sliced sphere/cone of varying geometrical complexity.

PIV Uncertainty Methodologies for CFD Code Validation at the MIR Facility

PIV Uncertainty Methodologies for CFD Code Validation at the MIR Facility PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Currently, computational fluid dynamics (CFD) is widely used in the nuclear thermal hydraulics field for design and safety analyses. To validate CFD codes, high quality multi dimensional flow field data are essential. The Matched Index of Refraction (MIR) Flow Facility at Idaho National Laboratory has a unique capability to contribute to the development of validated CFD codes through the use of Particle Image Velocimetry (PIV). The significance of the MIR facility is that it permits non intrusive velocity measurement techniques, such as PIV, through complex models without requiring probes and other instrumentation that disturb the flow. At the heart of any PIV calculation is the cross-correlation, which is used to estimate the displacement of particles in some small part of the image over the time span between two images. This image displacement is indicated by the location of the largest peak. In the MIR facility, uncertainty quantification is a challenging task due to the use of optical measurement techniques. Currently, this study is developing a reliable method to analyze uncertainty and sensitivity of the measured data and develop a computer code to automatically analyze the uncertainty/sensitivity of the measured data. The main objective of this study is to develop a well established uncertainty quantification method for the MIR Flow Facility, which consists of many complicated uncertainty factors. In this study, the uncertainty sources are resolved in depth by categorizing them into uncertainties from the MIR flow loop and PIV system (including particle motion, image distortion, and data processing). Then, each uncertainty source is mathematically modeled or adequately defined. Finally, this study will provide a method and procedure to quantify the experimental uncertainty in the MIR Flow Facility with sample test results.

A Proposed Framework for Computational Fluid Dynamics Code Calibration/validation

A Proposed Framework for Computational Fluid Dynamics Code Calibration/validation PDF Author:
Publisher:
ISBN:
Category : Computational fluid dynamics
Languages : en
Pages : 12

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Book Description
The paper reviews the terminology and methodology that have been introduced during the last several years for building confidence n the predictions from Computational Fluid Dynamics (CID) codes. Code validation terminology developed for nuclear reactor analyses and aerospace applications is reviewed and evaluated. Currently used terminology such as ''calibrated code, '' ''validated code, '' and a ''validation experiment'' is discussed along with the shortcomings and criticisms of these terms. A new framework is proposed for building confidence in CFD code predictions that overcomes some of the difficulties of past procedures and delineates the causes of uncertainty in CFD predictions. Building on previous work, new definitions of code verification and calibration are proposed. These definitions provide more specific requirements for the knowledge level of the flow physics involved and the solution accuracy of the given partial differential equations. As part of the proposed framework, categories are also proposed for flow physics research, flow modeling research, and the application of numerical predictions. The contributions of physical experiments, analytical solutions, and other numerical solutions are discussed, showing that each should be designed to achieve a distinctively separate purpose in building confidence in accuracy of CFD predictions. A number of examples are given for each approach to suggest methods for obtaining the highest value for CFD code quality assurance.

Verification and Validation in Scientific Computing

Verification and Validation in Scientific Computing PDF Author: William L. Oberkampf
Publisher: Cambridge University Press
ISBN: 1139491768
Category : Computers
Languages : en
Pages : 782

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Book Description
Advances in scientific computing have made modelling and simulation an important part of the decision-making process in engineering, science, and public policy. This book provides a comprehensive and systematic development of the basic concepts, principles, and procedures for verification and validation of models and simulations. The emphasis is placed on models that are described by partial differential and integral equations and the simulations that result from their numerical solution. The methods described can be applied to a wide range of technical fields, from the physical sciences, engineering and technology and industry, through to environmental regulations and safety, product and plant safety, financial investing, and governmental regulations. This book will be genuinely welcomed by researchers, practitioners, and decision makers in a broad range of fields, who seek to improve the credibility and reliability of simulation results. It will also be appropriate either for university courses or for independent study.

Rechtswissenschaft, Sozial-und Wirtschaftswissenschaften, Politik

Rechtswissenschaft, Sozial-und Wirtschaftswissenschaften, Politik PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description


AIAA Guide for the Verification and Validation of Computational Fluid Dynamics Simulations

AIAA Guide for the Verification and Validation of Computational Fluid Dynamics Simulations PDF Author: American Institute of Aeronautics and Astronautics
Publisher: AIAA (American Institute of Aeronautics & Astronautics)
ISBN: 9781563472855
Category : Computational fluid dynamics
Languages : en
Pages : 0

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Book Description
This document defines a number of key terms, discusses fundamental concepts, and specifies general procedures for conducting verification and validation of computational fluid dynamics simulations. It's goal is to provide a foundation for the major issues and concepts in verification and validation. However, it does not recommend standards in these areas because a number of important issues are not yet resolved.

A Proposed Framework for Computational Fluid Dynamics Code Calibration

A Proposed Framework for Computational Fluid Dynamics Code Calibration PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 12

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Book Description
The paper reviews the terminology and methodology that have been introduced during the last several years for building confidence n the predictions from Computational Fluid Dynamics (CID) codes. Code validation terminology developed for nuclear reactor analyses and aerospace applications is reviewed and evaluated. Currently used terminology such as ''calibrated code, '' ''validated code, '' and a ''validation experiment'' is discussed along with the shortcomings and criticisms of these terms. A new framework is proposed for building confidence in CFD code predictions that overcomes some of the difficulties of past procedures and delineates the causes of uncertainty in CFD predictions. Building on previous work, new definitions of code verification and calibration are proposed. These definitions provide more specific requirements for the knowledge level of the flow physics involved and the solution accuracy of the given partial differential equations. As part of the proposed framework, categories are also proposed for flow physics research, flow modeling research, and the application of numerical predictions. The contributions of physical experiments, analytical solutions, and other numerical solutions are discussed, showing that each should be designed to achieve a distinctively separate purpose in building confidence in accuracy of CFD predictions. A number of examples are given for each approach to suggest methods for obtaining the highest value for CFD code quality assurance.

Code Validation Studies of High-enthalpy Flows

Code Validation Studies of High-enthalpy Flows PDF Author: Graham V. Candler
Publisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 70

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Book Description
During the past three years, we have worked to develop and analyze a high-enthalpy flow dataset for CFD code validation. In collaboration with CUBRC Inc. personnel, we designed the experimental conditions for the double-cone geometry used in previous low-enthalpy nitrogen tests. We then used our standard CFD codes and thermo-chemical models to analyze these flows. In general, the comparisons with nitrogen flows are good, even at high enthalpy (10MJ/kg). But the comparisons between predictions and experiments for air above 5MJ/kg is poor. We find that as the enthalpy increases, the agreement gets worse. In particular, the CFD predicts that the separation zone decreases in size much more rapidly than given in the experiments.

A Practical Guide to Large Scale Computational Fluid Dynamics

A Practical Guide to Large Scale Computational Fluid Dynamics PDF Author: Ian Eames
Publisher: Wiley
ISBN: 9781119212065
Category : Technology & Engineering
Languages : en
Pages : 300

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Book Description
A Practical Guide to Large Scale Computational Fluid Dynamics Ian Eames, Christian Klettner and Andre Nicolle University College London, UK A practical guide to large scale computational fluid dynamics This book is a practical guide to large scale computational fluid dynamics which covers the main elements in writing large scale efficient fluid dynamics codes before considering the applications of these codes. A Practical Guide to Large Scale Computational Fluid Dynamics begins with an overview of fluid mechanics and the different methods (experimental, analytical and numerical) of analyzing fluid problems. It provides an introduction to the finite element method and the computational challenges encountered when writing largescale code and handling large data sets. The qualitative and quantitative diagnostics, which are essential to gaining physical insight, are presented and given in the fields of turbulence, fluid-structure interaction and free-surface flows. Finally, future trends are considered. Key features: Review of programming paradigms and open source high performance libraries which can be used to cut code development time. Extensive presentation of diagnostics which will help both numerical and experimental researchers. Provides validation cases which include a comprehensive list of common benchmark examples. Conceptual challenges from turbulent flows, fluid structure interaction and free surface flows are covered. Current state of the art research is described. Accompanied by a website hosting software and tutorials. The book is essential reading for postgraduate students, post-doctoral researchers and principal investigators who are writing large scale fluid mechanics codes and working with large datasets.