scholarly journals Hydromagnetic instability of a power-law liquid film flowing down a vertical cylinder using numerical approximation approach techniques

2009 ◽  
Vol 33 (4) ◽  
pp. 1904-1914 ◽  
Author(s):  
Po-Jen Cheng ◽  
Kuo-Chi Liu
Author(s):  
Po-Jen Cheng ◽  
Kuo-Chi Liu

The paper investigates the stability theory of a thin power law liquid film flowing down along the outside surface of a vertical cylinder. The long-wave perturbation method is employed to solve for generalized linear kinematic equations with free film interface. The normal mode approach is used to compute the stability solution for the film flow. The degree of instability in the film flow is further intensified by the lateral curvature of cylinder. This is somewhat different from that of the planar flow. The analysis results also indicate that by increasing the flow index and increasing the radius of the cylinder the film flow can become relatively more stable as traveling down along the vertical cylinder.


2008 ◽  
Vol 24 (3) ◽  
pp. 241-252 ◽  
Author(s):  
P. -J. Cheng ◽  
K. -C. Liu

ABSTRACTThe influence of both the flow index and the cylinder size on the nonlinear hydrodynamic stability of a thin power law liquid film flowing down along the surface of a vertical cylinder is investigated. The long-wave perturbation method is employed to solve for generalized nonlinear kinematic equations with a free film interface. The normal mode approach is first used to compute the linear stability solution for the film flow. The method of multiple scales is then used to obtain the weakly nonlinear dynamics of the film flow for stability analysis. The stability criteria are discussed theoretically and numerically and stability diagrams are obtained. The modeling results indicate that by increasing the flow index and increasing the radius of the cylinder the film flow can become relatively more stable as traveling down along the vertical cylinder.


2008 ◽  
Vol 130 (7) ◽  
Author(s):  
Po-Jen Cheng

The long-wave perturbation method is employed to investigate the nonlinear hydromagnetic stability of a thin electrically conductive power-law liquid film flowing down a vertical cylinder. In contrast to most previous studies presented in literature, the solution scheme employed in this study is based on a numerical approximation approach rather than an analytical method. The modeling results reveal that the stability of the film flow system is weakened as the radius of the cylinder is reduced. However, the flow stability can be enhanced by increasing the intensity of the magnetic field and the flow index.


1978 ◽  
Vol 45 (1) ◽  
pp. 19-24 ◽  
Author(s):  
V. Narayanamurthy ◽  
P. K. Sarma

The dynamics of accelerating, laminar non-Newtonian falling liquid film is analytically solved taking into account the interfacial shear offered by the quiescent gas adjacent to the liquid film under adiabatic conditions of both the phases. The results indicate that the thickness of the liquid film for the assumed power law model of the shear deformation versus the shear stress is influenced by the index n, the modified form of (Fr/Re). The mathematical formulation of the present analysis enables to treat the problem as a general type from which the special case for Newtonian liquid films can be derived by equating the index in the power law to unity.


1995 ◽  
Vol 17 (2) ◽  
pp. 34-39
Author(s):  
Nguyen Van Que

A numerical solution has been presented for free convection flow of power law fluid in a vertical cylinder of finite height. The average velocity along the channel and the heat transfer have been calculated. Graphs of velocities and temperature are shown. The results show good agreement with analytic one in the asymptotic case.


Author(s):  
M. V. Pham ◽  
F. Plourde ◽  
S. K. Doan

Thermal transfers occurring in the vicinity of an air-liquid interface have been studied numerically through a Large Eddy Simulation technique. Results obtained clearly show the unsteady response of the liquid film submitted to such thermal stress. Structures are created at the interface in a very small layer and it has been found that turbulence acts strongly in that layer. Moreover, even if the configuration studied tends to weaken buoyancy, the dissipation was found to obey a −3 power law. This clearly indicates that the buoyancy pilots the way turbulence behaves on the flow field; the latter is mainly characterized by a strong mixing phenomenon taking place in the already identified layer at the interface.


2003 ◽  
Vol 15 (10) ◽  
pp. 2973 ◽  
Author(s):  
Steven J. Weinstein ◽  
Kenneth J. Ruschak ◽  
Kam C. Ng

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