TITLE:
Influence of Rotating Speed Ratio on the Annular Turbulent Flow between Two Rotating Cylinders
AUTHORS:
M. Raddaoui
KEYWORDS:
Rotating Flows; Annular Flows; Speed Ratio; Numerical Simulation; RSM Model; Boundary Layers;Turbulence
JOURNAL NAME:
Journal of Modern Physics,
Vol.4 No.7,
July
15,
2013
ABSTRACT:
Rotating flows represent a very interesting area for researchers and
industry for their extensive use in industrial and domestic machinery and
especially for their great energy potential, annular flows are an example that draws
the attention of researchers in recent years. The best design and optimization of
these devices require knowledge of thermal, mechanical and hydrodynamic characteristics
of flows circulating in these devices. An example of hydrodynamic parameters is
the speed of rotation of the moving walls. This work is to study numerically the
influence of the rotating speed ratio Γ of the two moving cylinders on the mean
and especially on the turbulent quantities of the turbulent flow in the annular
space. The numerical simulation is based on one-point statistical modeling using
a low Reynolds number second-order full stress transport closure (RSM model), simulation
code is not a black box but a completely transparent code where we can intervene at any step of the calculation. We have varied Γ
from -1.0 to 1.0 while maintaining always the external cylinder with same speed
Ω. The results show that the turbulence structure, profiles of mean velocities and
the nature of the boundary layers of the mobile walls depend enormously on the ratio
of speeds. The level of turbulence measured by the kinetic energy of turbulence
and the Reynolds stresses shows well that the ratio Γ is an interesting parameter
to exploit turbulence in this kind of annular flows.