TY - GEN A1 - Tsai, Pei-Yun A1 - Schmidt, Heiko A1 - Klein, Marten T1 - Theoretical analysis and stochastic modeling of turbulent heat transfer in annular pipe flows T2 - 77th Annual Meeting of the Division of Fluid Dynamics, November 24–26, 2024; Salt Lake City, Utah N2 - Heat transfer in annular pipes is determined by the thermal and momentum boundary layer at the cylindrical inner and outer walls, respectively. The relative contributions are expressed by a local Nusselt number that depends on the radius ratio, the Prandtl number, and the Reynolds number. Direct numerical simulation (DNS) has been used previously to infer closure relations constrained to weakly turbulent flow due to numerical resource requirements. Here, stochastic one-dimensional turbulence (ODT) is utilized as a standalone tool as an alternative to DNS. ODT offers full-scale resolution along a representative radial domain, providing predictive capabilities relative to a calibrated reference case at a radically reduced cost. On average, ODT obeys radial balance equations compatible with the Navier-Stokes equations. Separating the boundary layer into a diffusion and a mixing-length dominated region in cylindrical geometry yields wall-curvature corrections at the inner wall. The proposed expressions can be used to enhance prescribed wall functions, for example, in Reynolds-averaged Navier-Stokes simulations. KW - heat transfer KW - boundary layer theory KW - stochastic modeling KW - one-dimensional turbulence KW - spanwise wall curvature KW - heated pipe flow Y1 - 2024 UR - https://meetings.aps.org/Meeting/DFD24/Session/T40.7 PB - American Physical Society ER - TY - CHAP A1 - Klein, Marten A1 - Tsai, Pei-Yun A1 - Schmidt, Heiko ED - Dillmann, Andreas ED - Heller, Gerd ED - Krämer, Ewald ED - Wagner, Claus ED - Weiss, Julien T1 - Stochastic Modeling and Large-Eddy Simulation of Heated Concentric Coaxial Pipes T2 - New Results in Numerical and Experimental Fluid Mechanics XIV, STAB/DGLR Symposium 2022 N2 - Turbulent concentric coaxial pipe flows are numerically investigated as canonical problem addressing spanwise curvature effects on heat and momentum transfer that are encountered in various engineering applications. It is demonstrated that the wall-adapting local eddy-viscosity (WALE) model within a large-eddy simulation (LES) framework, without model parameter recalibration, has limited predictive capabilities as signalized by poor representation of wall curvature effects and notable grid dependence. The identified lack in the modeling of radial transport processes is therefore addressed here by utilizing a stochastic one-dimensional turbulence (ODT) model. A standalone ODT formulation for cylindrical geometry is used in order to assess to which extent the predictability can be expected to improve by utilizing an advanced wall-modeling strategy. KW - Heat and mass transfer KW - Stochastic turbulence modeling KW - Spanwise curvature effects KW - Pipe flow Y1 - 2024 SN - 978-3-031-40482-5 SN - 978-3-031-40481-8 U6 - https://doi.org/10.1007/978-3-031-40482-5_41 SN - 1612-2909 SN - 1860-0824 N1 - This research is supported by the German Federal Government, the Federal Ministry of Education and Research and the State of Brandenburg within the framework of the joint project EIZ: Energy Innovation Center (project numbers 85056897 and 03SF0693A) with funds from the Structural Development Act (Strukturstärkungsgesetz) for coal-mining regions. M.K. acknowledges support by the BTU Graduate Research School (Conference Travel Grant). SP - 435 EP - 444 PB - Springer CY - Cham ER - TY - GEN A1 - Tsai, Pei-Yun A1 - Schmidt, Heiko A1 - Klein, Marten T1 - Investigating Reynolds number effects in turbulent concentric coaxial pipe flow using stochastic one-dimensional turbulence modeling T2 - Proceedings in Applied Mathematics and Mechanics N2 - The present study numerically investigates turbulent momentum transfer in concentric coaxial (annular) pipe flow with small radius ratios (𝜂 = 𝑅𝑖∕𝑅𝑜 = 0.1,0.04,0.02). To model the flow, a stochastic one-dimensional turbulence (ODT) model formulated for cylindrical geometry is used that provides full-scale resolution along a representative radial coordinate. The present investigation extends the model validation by Tsai et al. (PAMM,22:e202200272, 2023), to radius ratios smaller than 0.1 and addresses boundary layers with strong span-wise curvature effects. The focus is on the assessment and analysis of statistical flow features in the vicinity of the inner cylinder wall, particularly in cases with small radius ratios. Following Boersma & Breugem (Flow Turbul. Com-bust.,86:113–127, 2011), classical boundary-layer and mixing-length theory is utilized to analyze the model predictions. The results demonstrate that the ODT model captures leading-order curvature and mixing-length effects by its physics-compatible construction. Utilizing the model for extrapolation to high Reynolds numbers inaccessible to conventional high-fidelity numerical approaches shows that curvature effects persist and nonlocally affect the entire boundary layer. The model results provide support for a spanwise-curvature-modified wall function. KW - turbulent coaxial pipe flow KW - stochastic modeling KW - one-dimensional turbulence KW - spanwise curvature KW - turbulent boundary layer KW - high Reynolds number Y1 - 2023 U6 - https://doi.org/10.1002/pamm.202300167 SN - 1617-7061 N1 - Proceedings of the GAMM Annual Meeting 2023, Dresden, Germany VL - 23 IS - 4 SP - 1 EP - 8 ER - TY - GEN A1 - Tsai, Pei-Yun A1 - Schmidt, Heiko A1 - Klein, Marten T1 - Stochastic modeling of asymmetric turbulent boundary layers in annular pipe flow Y1 - 2023 UR - https://www-docs.b-tu.de/fg-stroemungsmodellierung/public/Tsai_2023_poster_PragueSummerSchoolX.pdf U6 - https://doi.org/10.13140/RG.2.2.18789.78567 N1 - Stochastics in Fluids Summer School and Workshop 2023, Czech Academy of Sciences Institute of Mathematics, Prague, Czech Republic ER -