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Theoretical and Experimental Study of Selective Withdrawal From Two Layer Fluid With Topographic Effects
, M.Sc. Thesis Sharif University of Technology ; Jamali, Mirmosaddegh (Supervisor)
Abstract
Selective withdrawal is withdrawing water with desired quality from a reservoir and has many applications in water quality management of reservoirs. Topographic effects such as a sill alter the withdrawal layer properties. In this study, the effect of a sill on selective withdrawal of a two-layer fluid through a line sink at the bottom of a rectangular reservoir is studied using two-layer hydraulics theory, numerical model and laboratory experiments. Experiments were done for studying surge, and the results are compared with two-layer hydraulics theory and numerical model. After reservoir gate is opened, some disturbances upstream of sill lead to creation of a surge. The results show this is...
Growth and damping of interfacial waves on a diffuse interface
, Article Environmental Fluid Mechanics ; Volume 16, Issue 2 , 2016 , Pages 401-412 ; 15677419 (ISSN) ; Jamali, M ; Lawrence, G. A ; Seymour, B ; Sharif University of Technology
Abstract
The resonant interaction of surface and internal waves produces a nonlinear mechanism for energy transfer among wave components in oceans, lakes, and estuaries. In many field situations, the stratification may be well approximated by a two-layer fluid with a diffuse interface. The growth and damping rates of sub-harmonic interfacial waves generated by a surface wave through a three-wave resonant interaction are measured in the laboratory. These measurements are compared with theoretical predictions. A diffuse interface reduces the damping rate and increases the growth rate. The predicted growth rate provides excellent comparison with the laboratory measurements. The inclusion of the effects...
Experimental Investigation of Long time Behavior of Interfacial Waves in a Two Layer Immiscible Fluid
, M.Sc. Thesis Sharif University of Technology ; Jamali, Mirmosadegh (Supervisor)
Abstract
The motion of a surface wave in a two-layer fluid can lead to generation of sub-harmonic interfacial waves through a nonlinear resonant interaction mechanism. The interfacial waves grow exponentially in time until they reach a maximum amplitude and then oscillate down to a final amplitude, referred to as ultimate amplitude, in long term. This may lead to considerable mixing of the layers in miscible fluid and increase the thickness of the diffuse layer. Experiments show that the diffuse layer causes frequency shift and decreases the ultimate amplitude. In this study, long time behavior of interfacial waves in a two layer immiscible fluid was investigated. A two-layer immiscible system...
Identification of evolving interfacial waves by spatial harmonic analysis
, Article Environmental Fluid Mechanics ; Volume 17, Issue 4 , 2017 , Pages 647-664 ; 15677419 (ISSN) ; Safaie, A ; Jamali, M ; Sharif University of Technology
Springer Netherlands
2017
Abstract
This paper is concerned with an analysis of image processing data to identify interfacial waves at the interface between two fluid layers in a laboratory flume. The interfacial waves are excited through a non-linear resonant interaction with a surface wave traveling in a wave flume filled with a two-layer fluid. A spatial harmonic analysis is proposed to extract information about the nonlinear evolution of the constituent waves from the interface oscillation data. The analysis is capable of handling different stages of the resonance in the wave flume and gives accurate and consistent results on time variations of the wave amplitudes. Contrary to a temporal harmonic analysis, the proposed...
Analytical and Experimental Study of Nonlinear Resonant Interaction Between Surface Wave and Harmonic Interfacial Waves
, M.Sc. Thesis Sharif University of Technology ; Jamali, Mirmosaddegh (Supervisor)
Abstract
Lakes and estuaries are usually density stratified. Interaction between surface and interfacial waves causes turbulence in such systems. The interaction between a surface wave and harmonic interfacial waves has been previously studied analytically using a perturbation scheme. However, the calculations have been long and time consuming. In this study, we improve the solution process by using a variational approach to mathematical modeling. We also present the results of an experimental study of the problem. The experiments were video-taped and were analyzed using an image processing method. The conditions leading to generation of harmonic interfacial waves are determined. Limitations of the...
Cubic nonlinear analysis of interaction between a surface wave and two interfacial waves in an open two-layer fluid
, Article Fluid Dynamics Research ; Volume 44, Issue 5 , June , 2012 ; 01695983 (ISSN) ; Jamali, M ; Sharif University of Technology
IOP
2012
Abstract
A third-order asymptotic analysis is conducted to study the three-dimensional resonant interaction between a monochromatic progressive surface wave and two oblique interfacial waves in an open, lightly viscous, two-layer fluid of intermediate depth. By solving the evolution equations of the waves, the short- and long-term behaviors of the interfacial waves are studied. The analysis provides a correction to the second-order theory. The results indicate that the third-order analysis predicts a much lower limit on the growth of the interfacial waves than the second-order theory. Furthermore, in the long term, viscous effects cause the interfacial wave amplitudes to approach a constant value....
Evolution of sub-harmonic interfacial waves generated by a surface wave through a three-wave interaction
, Article Scientia Iranica ; Volume 19, Issue 2 , 2012 , Pages 225-233 ; 10263098 (ISSN) ; Jamali, M ; Sharif University of Technology
2012
Abstract
Higher-order effects in three-wave resonant interaction of a surface wave, with a pair of interfacial waves in a two-layer fluid, are studied theoretically. Following an initial rapid growth, the interfacial waves approach a steady state of constant amplitude. An explicit solution is presented for transition to the ultimate state of the interaction. It is shown that for interaction in a wave flume, it is necessary to include a 2nd pair of the interfacial waves, resulting from a reflection of the original pair in the analysis. The effects of different parameters on the dynamics of the interaction are investigated. The results indicate that a faster initial growth does not necessarily lead to...
Analytical cubic solution to weakly nonlinear interactions between surface and interfacial waves
, Article Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, 31 May 2009 through 5 June 2009, Honolulu, HI ; Volume 6 , 2009 , Pages 625-630 ; 9780791843468 (ISBN) ; Jamali, M ; Sharif University of Technology
Abstract
Resonant interaction between one surface wave and two oblique interfacial waves is analyzed in a three dimensional system of a finite-depth, two-layer fluid. A third order perturbation analysis is carried out to obtain the evolution equations of the waves amplitudes. Taking the waves amplitudes as the perturbation small parameter, the evolution equations of the waves are solved simultaneously to obtain the short and long term behavior of the interfacial waves. In contrast to the second order analysis, the current analysis shows that after an initial exponential growth period, the interfacial waves stop growing and stabilize. Furthermore, the influences of surface wave frequency, density...