Two-fluid boundary layer stability

1998-11-01
Özgen, Serkan
Sarma, GSR
The stability of a two-fluid boundary layer is investigated. A boundary layer shears a second fluid that is bounded by the wall and the shearing fluid. The eigenvalue problem governing the linear stability of the configuration is solved using an efficient shooting-search method. Besides the Tollmien-Schlichting mode (hard mode) found in the classical hydrodynamical stability theory an additional Yih-mode (interfacial mode) exists due to the two-fluid interface. Effects of viscosity and density stratifications, thickness of the bounded fluid, gravity, surface tension as well as the non-Newtonian character of the lower fluid on the stability characteristics are determined. The interfacial mode is found to be very sensitive against viscosity stratification. However, with a highly viscous liquid layer, the system approaches a single-layer behavior. The shear-thinning non-Newtonian liquid layer is observed to have a stabilizing effect for both of the modes. Surface tension is stabilizing for shea waves for the interfacial mode but a more complex effect was observed for the hard mode. Gravity is stabilizing with a favorable density stratification. Density stratification alone is destabilizing for low and moderate values of this parameter but becomes stabilizing for higher values. When the external boundary layer profile is turbulent, the interfacial mode is more likely to be observed in an experiment. Agreement of the obtained results with experimental, theoretical and numerical results reported in the literature is good. This is encouraging as the study is intended for solving the stability characteristics of de/anti-icing fluid-air systems and comparing the results with the experimental data when they become available. (C) 1998 American Institute of Physics. [S1070-6631(98)01811-X].
PHYSICS OF FLUIDS

Suggestions

TURBULENT BOUNDARY-LAYER AND THE EFFECT OF CRITICAL ROUGHNESS REYNOLDS-NUMBERS ON THE RECOVERY LENGTH BEHIND AN ISOLATED SPHERICAL ROUGHNESS ELEMENT UNDER VARIABLE PRESSURE-GRADIENT
Albayrak, Kahraman (1990-03-01)
The transition characteristics and the boundary layer development behind an isolated spherical roughness element were investigated in an open-circuit, suction-type wind tunnel. The experiments were performed upon a smooth aluminiuim flat plate placed in the test section of the tunnel. The desired pressure gradient was obtained by means a false roof placed in the test section. In this article, emphasis is given to the recovery length of the turbulent boundary layer behind an isolated spherical roughness ele...
High Speed Couette—Poiseuille Flow Stability in Reverse Flow Conditions
Ebrinç, Ali Aslan; Özgen, Serkan; Dursunkaya, Zafer (2006-08-21)
The linear stability of reverse high speed-viscous plane Couette – Poiseuille flow is investigated numerically. The conservation equations along with Sutherland’s viscosity law are studied using a second order finite difference scheme. Basic velocity and temperature distributions are perturbed by a small amplitude normal-mode disturbance. Small amplitude disturbance equations are solved numerically using a global method to find all the eigenvalues at finite Reynolds numbers. The results indicate that instab...
An investigation of liquefaction effects on piers and piles of segmental precast balanced cantilever bridges
Gündüz, Özer; Caner, Alp; Department of Earthquake Studies (2019)
In this thesis, the seismic behavior of a typical segmental precast balanced cantilever bridge over liquefiable soils is investigated. Liquefaction is a phenomenon that is triggered by large movements of the sand layer during earthquakes and cause damage to structures. The subject is still under investigation, approaches for liquefaction induced lateral spreading calculations can be found in the literature. Inertial and kinematic effects of the lateral spreading were studied with a total of four different a...
Wall functions for boundary roughness prediction in uniform channel flows
Aydın, İsmail (null; 2017-08-18)
Boundary roughness is an important hydraulic parameter in describing dynamics of free surface flows. There is no direct method to estimate the possible boundary resistance in natural environment. Available empirical formulations are based on the particle
Two-dimensional translation, rocking, and waves in a building during soil-structure interaction excited by a plane earthquake SV-wave pulse
Gicev, Vlado; Trifunac, Mihailo D.; Orbovic, Nebojsa (2016-09-01)
two-dimensional (2-D) model of a building supported by a rectangular, flexible foundation embedded in the soil is analyzed for excitation by an incident plane SV-wave. The incidence is below the critical angle. The building is assumed to be anisotropic and linear while the soil and the foundation are assumed to be isotropic and can experience nonlinear deformations. In general the work spent for the development of nonlinear strains in the soil can consume a significant part of the input wave energy and thus...
Citation Formats
S. Özgen and G. Sarma, “Two-fluid boundary layer stability,” PHYSICS OF FLUIDS, pp. 2746–2757, 1998, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/57072.