Hello,
The k-ω model is currently favoured for turbulent flow CFD simulations within arteries, as it has performed better than other models when compared to experimental data. The k-ω model is a two-equation model that solves transport equations for turbulent kinetic energy and the specific dissipation rate (ω), which is the turbulent dissipation rate (ε), per unit turbulent kinetic energy. It is advisable to use the k-ω model in simulations involving turbulent flow through carotid arteries.
The Reynolds number is not high, and accuracy can mean saving of lives. Do not use a turbulence model, perform a direct simulation (DNS) resolving all temporal and spatial scales with an appropriate function for the viscosity (shear thinning character). This can be done with any numerical code solving the Navier-Stokes equations, and the numerical costs will be affordable.
Chapter Advanced Computational Models for Disturbed and Turbulent Fl...
I think it depends on the simulated resolution, just use kOmega model or the affiliated SST model might lose some resolution without resolving the eddies, although the eddies might be quite less to some extent. I think use LES or DDES is also suitable for simulating this kind of pipe flow, see this POF paper:
On the wake flow behind a sphere in a pipe flow at low Reynolds numbers
In this range of Reynolds numbers, I'd advise you to use direct simulations of the lattice Boltzmann type. They can accurately deal with complex boundary conditions and yield pretty good results for wake problems for instance something k-omega does not to my knowledge
Yves Pomeau
Resources, and academic tools on turbulent single-phase and multiphase flows are availble on the project:
https://www.researchgate.net/project/Single-Phase-and-Multiphase-Turbulent-Flows-SMTF-in-Nature-and-Engineering-Applications
An important point to be considered in modeling blood flows is related to the behavior of blood: at what extend can we consider that blood is a Newtonian fluid ?
It is not Newtonian but shear thinning and it has to be accounted for of course.
In this case, my opinion is that turbulence models are only suitable at high apparent Reynolds Numbers
Volodymyr Brazhenko
could you please explain agree on what ?Markus J. Kloker Sainulabdeen Asif could you please tell us what turbulence model is used and what particular modulation of the terms closures are completed to take into account the non-newtonian behavior of blood, particularly for relatively low apparent Reynolds numbers ?
Volodymyr Brazhenko
Thank you for your replay, I thought I missed something. Well, blood flows can be turbulent or laminar: turbulent in the veins and in particular at the level of the vascular network of the myocardium and in the primary carotid. In blood vessels of smaller sizes the flows are most of the time laminar. The same goes for the respiratory system where the flow of air is turbulent in the trachea artery, and laminar in the bronchioles and in the pulmonary alveoli.
Academic resources on turbulent flows and turbulence models for single and multiphase flows are provided within the refrences of the following research project:
https://www.researchgate.net/project/Single-Phase-and-Multiphase-Turbulent-Flows-SMTF-in-Nature-and-Engineering-Applications
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