An improved k-ω turbulence model for FENE-P fluids without friction velocity dependence

2021 ◽  
Vol 90 ◽  
pp. 108799
Author(s):  
M. McDermott ◽  
P.R. Resende ◽  
M.C.T. Wilson ◽  
A.M. Afonso ◽  
D. Harbottle ◽  
...  
2020 ◽  
Vol 10 (22) ◽  
pp. 8140
Author(s):  
Michael McDermott ◽  
Pedro Resende ◽  
Thibaut Charpentier ◽  
Mark Wilson ◽  
Alexandre Afonso ◽  
...  

A viscoelastic turbulence model in a fully-developed drag reducing channel flow is improved, with turbulent eddies modelled under a k–ε representation, along with polymeric solutions described by the finitely extensible nonlinear elastic-Peterlin (FENE-P) constitutive model. The model performance is evaluated against a wide variety of direct numerical simulation data, described by different combinations of rheological parameters, which is able to predict all drag reduction (low, intermediate and high) regimes with good accuracy. Three main contributions are proposed: one with a simplified viscoelastic closure for the NLTij term (which accounts for the interactions between the fluctuating components of the conformation tensor and the velocity gradient tensor), by removing additional damping functions and reducing complexity compared with previous models; second through a reformulation for the closure of the viscoelastic destruction term, Eτp, which removes all friction velocity dependence; lastly by an improved modified damping function capable of predicting the reduction in the eddy viscosity and thus accurately capturing the turbulent kinetic energy throughout the channel. The main advantage is the capacity to predict all flow fields for low, intermediate and high friction Reynolds numbers, up to high drag reduction without friction velocity dependence.


2011 ◽  
Vol 38 (19) ◽  
pp. n/a-n/a ◽  
Author(s):  
Akito Tsutsumi ◽  
Olivier Fabbri ◽  
Anne Marie Karpoff ◽  
Kohtaro Ujiie ◽  
Atsushi Tsujimoto

2020 ◽  
Vol 77 (11) ◽  
pp. 3891-3906
Author(s):  
Xiping Zeng ◽  
Yansen Wang

AbstractA k–ε turbulence model for the stable atmosphere is extended for the convective atmosphere. The new model represents the buoyancy-induced increase in the kinetic energy and scale of eddies, and is consistent with the Monin–Obukhov similarity theory for convective atmospheric boundary layers (ABLs). After being incorporated into an ABL model with the Coriolis force, the model is tested by comparing the ABL model results with the Businger–Dyer (BD) relationship. ABL model simulations are carried out to reveal the sensitivity of the vertical wind profile to model parameters (e.g., the Obukhov length, friction velocity, and geostrophic wind). When the friction velocity is consistent with geostrophic wind speed (or the turbulence in the inner regime is in equilibrium with that in the outer regime), the modeled wind profile is close to the BD relationship near the ground surface. Otherwise, the modeled wind profile deviates from the BD relationship, resembling the hockey stick transition model.


2013 ◽  
Vol 40 (3) ◽  
pp. 185-203
Author(s):  
Dhahri Maher ◽  
Bellakhel Ghazi ◽  
Chahed Jamel

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