Mesh Sensitivity Analysis of Axisymmetric Models for Smooth–Turbulent Transient Flows

The current paper focuses on the assessment of radial mesh influence on the description of the transient event obtained by an axisymmetric model. The objective is to reduce computational effort while accurately calculating hydraulic transients in smooth–turbulent pressurized pipes. The analyzed pipe...

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Main Authors: Pedro Leite Ferreira, Dídia Isabel Cameira Covas
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Fluids
Subjects:
Online Access:https://www.mdpi.com/2311-5521/9/11/268
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author Pedro Leite Ferreira
Dídia Isabel Cameira Covas
author_facet Pedro Leite Ferreira
Dídia Isabel Cameira Covas
author_sort Pedro Leite Ferreira
collection DOAJ
description The current paper focuses on the assessment of radial mesh influence on the description of the transient event obtained by an axisymmetric model. The objective is to reduce computational effort while accurately calculating hydraulic transients in smooth–turbulent pressurized pipes. The analyzed pipe system has a reservoir–pipe–valve configuration with an inner diameter of 0.02 m and a total length of 14.96 m, with the initial discharge being equal to 120 × 10<sup>−3</sup> L/s (Re = 7638). An extensive study is carried out with 80 geometric sequence meshes by varying the total number of cylinders, the geometric common ratio, and the pipe axial discretization. The benefit of increasing the geometric common ratio is highlighted. A detailed comparison between two meshes is presented, in which the best mesh (i.e., the one with the lowest computational effort) has a three-fold higher value of the geometric common ratio. The two meshes show small differences for the instantaneous valve closure, limited to a time interval immediately after the arrival of the pressure surge and only during the first pressure wave. The dynamic characterization of the transient phenomenon demonstrates the in-depth consistency between the model results and the hydraulic transients’ phenomenon in terms of the piezometric head, the wall shear stress, and the mean velocity time-history, in comparison to the results obtained with the shear stress, lateral velocity, and axial velocity profiles.
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spelling doaj-art-97059e972d9d44e5bb096f08337c420f2024-11-26T18:04:11ZengMDPI AGFluids2311-55212024-11-0191126810.3390/fluids9110268Mesh Sensitivity Analysis of Axisymmetric Models for Smooth–Turbulent Transient FlowsPedro Leite Ferreira0Dídia Isabel Cameira Covas1Department of Civil Engineering, Polytechnic of Porto, 4249-015 Porto, PortugalCERIS, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, PortugalThe current paper focuses on the assessment of radial mesh influence on the description of the transient event obtained by an axisymmetric model. The objective is to reduce computational effort while accurately calculating hydraulic transients in smooth–turbulent pressurized pipes. The analyzed pipe system has a reservoir–pipe–valve configuration with an inner diameter of 0.02 m and a total length of 14.96 m, with the initial discharge being equal to 120 × 10<sup>−3</sup> L/s (Re = 7638). An extensive study is carried out with 80 geometric sequence meshes by varying the total number of cylinders, the geometric common ratio, and the pipe axial discretization. The benefit of increasing the geometric common ratio is highlighted. A detailed comparison between two meshes is presented, in which the best mesh (i.e., the one with the lowest computational effort) has a three-fold higher value of the geometric common ratio. The two meshes show small differences for the instantaneous valve closure, limited to a time interval immediately after the arrival of the pressure surge and only during the first pressure wave. The dynamic characterization of the transient phenomenon demonstrates the in-depth consistency between the model results and the hydraulic transients’ phenomenon in terms of the piezometric head, the wall shear stress, and the mean velocity time-history, in comparison to the results obtained with the shear stress, lateral velocity, and axial velocity profiles.https://www.mdpi.com/2311-5521/9/11/268hydraulic transientunsteady frictionaxisymmetric modelmesh optimizationsmooth–turbulent transient flows
spellingShingle Pedro Leite Ferreira
Dídia Isabel Cameira Covas
Mesh Sensitivity Analysis of Axisymmetric Models for Smooth–Turbulent Transient Flows
Fluids
hydraulic transient
unsteady friction
axisymmetric model
mesh optimization
smooth–turbulent transient flows
title Mesh Sensitivity Analysis of Axisymmetric Models for Smooth–Turbulent Transient Flows
title_full Mesh Sensitivity Analysis of Axisymmetric Models for Smooth–Turbulent Transient Flows
title_fullStr Mesh Sensitivity Analysis of Axisymmetric Models for Smooth–Turbulent Transient Flows
title_full_unstemmed Mesh Sensitivity Analysis of Axisymmetric Models for Smooth–Turbulent Transient Flows
title_short Mesh Sensitivity Analysis of Axisymmetric Models for Smooth–Turbulent Transient Flows
title_sort mesh sensitivity analysis of axisymmetric models for smooth turbulent transient flows
topic hydraulic transient
unsteady friction
axisymmetric model
mesh optimization
smooth–turbulent transient flows
url https://www.mdpi.com/2311-5521/9/11/268
work_keys_str_mv AT pedroleiteferreira meshsensitivityanalysisofaxisymmetricmodelsforsmoothturbulenttransientflows
AT didiaisabelcameiracovas meshsensitivityanalysisofaxisymmetricmodelsforsmoothturbulenttransientflows