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oai:recercat.cat:2117/4209172026-01-30T08:39:18Zcom_2072_1033col_2072_452950

Minimal flow unit of wall-bounded high-pressure transcritical turbulence Elmansy, Reda Mohamed Yousyf Abdallah Bandarrinha Monteiro, Carlos Alexandre Mellibovsky Elstein, Fernando Jofre Cruanyes, Lluís Universitat Politècnica de Catalunya. Departament de Mecànica de Fluids Universitat Politècnica de Catalunya. Doctorat en Enginyeria Mecànica, Fluids i Aeronàutica Universitat Politècnica de Catalunya. Departament de Física Universitat Politècnica de Catalunya. DF-GeoTech - Dinàmica de Fluids i Aplicacions Geofísiques i Tecnològiques Universitat Politècnica de Catalunya. GReCEF- Grup de Recerca en Ciència i Enginyeria de Fluids Àrees temàtiques de la UPC::Enginyeria mecànica::Mecànica de fluids Supercritical fluids Phase transitions Thermodynamic properties Signal processing Fluid mechanics Computational fluid dynamics Turbulent flows Fluids supercrítics The minimum domain size required to maintain fully developed wall-bounded turbulent flow in high-pressure transcritical regimes is analyzed using direct numerical simulations. The computations involve carbon dioxide at supercritical conditions with pressure P=Pc ¼ 2 (subscript c denotes critical value), confined between cold (temperature T=Tc ¼ 0:85) and hot (T=Tc ¼ 1:5) isothermal walls. The corresponding friction Reynolds numbers are Res 76 and 123 for the cold and hot walls, respectively. The study considers a large baseline domain of size Lx=d ¼ 4p, Ly=d ¼ 2, and Lz=d ¼ð8=3Þp in the streamwise, wall-normal, and spanwise directions, respectively, with d the half-channel height, as well as truncated setups along the streamwise and/or spanwise directions. The results show that rather small domains are sufficient to reproduce near-wall flow motions, while larger domains are needed to properly capture large-scale structures, especially within the log-law region. Additionally, the study confirms that the distance over which thermal interactions occur is shorter than the typical size of hydrodynamic structures, particularly so in the spanwise direction. This finding suggests that the minimum periodic domain size required in the high-pressure transcritical regime is comparable to that of the minimum flow unit established by other researchers for wall-bounded flows under standard pressure-temperature conditions. This work is funded by the European Union (ERC, SCRAMBLE, 101040379). Views and opinions expressed are, however, those of the authors only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. The authors also acknowledge support from the SGR program (2021-SGR-01045) of the Generalitat de Catalunya (Spain), the PID2023-150840OA-I00 grant of the Agencia Estatal de Investigación (AEI, Spain), and the computer resources at FinisTerrae III & MareNostrum and the technical support provided by CESGA & Barcelona Supercomputing Center (RES-IM-2023-1-0005, RES-IM-2023-2-0005). F.M. acknowledges support from the PID2020-114043GB-I00 and PID2023-150029NB-I00 grants of the AEI. Peer Reviewed Postprint (published version) 2024-12-01 Article Reda El Mansy [et al.]. Minimal flow unit of wall-bounded high-pressure transcritical turbulence. "Physics of fluids", 1 Desembre 2024, vol. 36, núm. 12, article 125182. 1070-6631 https://hdl.handle.net/2117/420917 10.1063/5.0243832 eng https://pubs.aip.org/aip/pof/article/36/12/125182/3326109/Minimal-flow-unit-of-wall-bounded-high-pressure info:eu-repo/grantAgreement/EC/HE/101040379/EU/Turbulence-On-a-Chip: Supercritically Overcoming the Energy Frontier in Microfluidics/SCRAMBLE info:eu-repo/grantAgreement/AEI//PID2023-150840OA-I00/Machine learning enriched data reconstruction of fluid flows for virtual interaction with engineering systems/METAFLUID-VERSE info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/PID2020-114043GB-I00/ES/COMPUTACION DE ALTO RENDIMIENTO DE ESTRUCTURAS HIDRODINAMICAS COHERENTES / info:eu-repo/grantAgreement/AEI//PID2023-150029NB-I00/Decodificación de la frontera del caos en problemas de convección térmica, cizalladura y centrífugos, con aplicación a flujos aeroespaciales/DECAF http://creativecommons.org/licenses/by/4.0/ Open Access Attribution 4.0 International 26 p. application/pdf application/pdf