Hydrodynamic limit of multiscale viscoelastic models for rigid particle suspensions

We study the multiscale viscoelastic Doi model for suspensions of Brownian rigid rod-like particles, as well as its generalization by Saintillan and Shelley for self-propelled particles. We consider the regime of a small Weissenberg number, which corresponds to a fast rotational diffusion compared to the fluid velocity gradient, and we analyze the resulting hydrodynamic approximation. More precisely, we show the asymptotic validity of macroscopic nonlinear viscoelastic models, in form of so-called ordered fluid models, as an expansion in the Weissenberg number. The result holds for zero Reynolds number in 3D and for arbitrary Reynolds number in 2D. Along the way, we establish several new well-posedness and regularity results for nonlinear fluid models, which may be of independent interest.Comment: 64 page

Derivation of an effective rheology for dilute suspensions of micro-swimmers

We provide a rigorous derivation of an effective rheology for dilute viscous suspensions of self-propelled particles. We derive at the limit an effective Stokes system with two additional terms. The first term corresponds to an effective viscosity that matches the famous Einstein's formula $\mu_{eff}=(1+ \frac{5}{2} \lambda)\mu$. The second additional term derived is an effective active stress $\sigma_1$ that appears as a forcing term $\lambda \, \text{div} \, \sigma_1$ in the fluid equation. We then investigate the effects of this term depending on the micro-swimmers nature and their distribution in the fluid.Comment: 32 pages, 2 figure

Radiographie et échographie des articulations synoviales intervertébrales cervicales du cheval. (Thèse confidentielle)

MAISONS-ALFORT-Ecole Vétérin (940462302) / SudocSudocFranceF

Recent achievements towards aero-structure gradient computation using high-fidelity CFD-CSM in the Onera ELSA software

International audienc

Transonic aeroelastic computations using Navier-Stokes equations

Communication to : International forum on aeroelasticity and structural dynamics (IFASD 2003), Amsterdam (Pays-Bas), June 04-06, 2003SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : 22419 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc