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Dynamics of the Wavy Film Flow Down an Inclined Plane. II. Extended Similarity Profile for Newtonian Liquids
Wein, Ondřej ; Tihon, Jaroslav
Macroscopic balance method is a classic approximation in the theory of wavy film flows, see Kapitza (1949), Prokopiou et al. (1991), Wein (1993), Hwang (1994). Due to the mathemati-cal complexity of the related Orr-Sommerfeld problem for non-Newtonian liquids, the macro-scopic balance could be the only accessible method of attacking the problem at present. In the present report, we try to improve the macroscopic balance (MB) method for the Newto-nian fluids by (i) including the effect of normal stress changes into the x-moment balance, and (ii) using more realistic estimate of the time-dependent velocity field. Within the 3rd-order long-wave asymptotic expansion, O(a3), the improved MB method provides the results (celerity, criti-cal Reynolds number, wave number, identical with the solution of the related Orr-Sommerfeld problem. The new results indicate that (i) the improved x-momentum macroscopic balance is a correctly formulated functional property of the velocity field, (ii) the similarity velocity fie ld assumption is too simplified to provide a reasonable estimates of the linear stability parameters within the 3rd-order analysis, (iii) the extended similarity profile, correct up to O(a2), guarantees the estimate of the three basic wave characteristics, c, Recrit, a, within the accuracy including O(a3) terms. Macroscopic balance method is a classic approximation in the theory of wavy film flows, see Kapitza (1949), Prokopiou et al. (1991), Wein (1993), Hwang (1994). Due to the mathemati-cal complexity of the related Orr-Sommerfeld problem for non-Newtonian liquids, the macro-scopic balance could be the only accessible method of attacking the problem at present. In the present report, we try to improve the macroscopic balance (MB) method for the Newto-nian fluids by (i) including the effect of normal stress changes into the x-moment balance, and (ii) using more realistic estimate of the time-dependent velocity field. Within the 3rd-order long-wave asymptotic expansion, O(a3), the improved MB method prov ides the results (celerity, criti-cal Reynolds number, wave number, identical with the solution of the related Orr-Sommerfeld problem. The new results indicate that (i) the improved x-momentum macroscopic balance is a correctly formulated functional property of the velocity field, (ii) the similarity velocity field assumption is too simplified to provide a reasonable estimates of the linear stability parameters within the 3rd-order analysis, (iii) the extended similarity profile, correct up to O(a2), guarantees the estimate of the three basic wave characteristics, c, Recrit, a, within the accuracy including O(a3) terms. Macroscopic balance method is a classic approximation in the theory of wavy film flows, see Kapitza (1949), Prokopiou et al. (1991), Wein (1993), Hwang (1994). Due to the mathemati-cal complexity of the related Orr-Sommerfeld problem for non-Newtonian liquids, the macro-scopic balance could be the only accessible method of attacking the problem at present. In the present report, we try to improve the macroscopic balance (MB) method for the Newto-nian fluids by (i) including the effect of normal stress changes into the x-moment balance, and (ii) using more realistic estimate of the time-dependent velocity field. Within the 3rd-order long-wave asymptotic expansion, O(a3), the improved MB method provides the results (celerity, criti-cal Reynolds number, wave number, identical with the solution of the related Orr-Sommerfeld problem. The new results indicate that (i) the improved x-momentum macroscopic balance is a correctly formulated functional property of the velocity field, (ii) the similarity velocity field assumption is too simplified to provide a reasonable estimates of the linear stability parameters within the 3rd-order analysis, (iii) the extended similarity profile, correct up to O(a2), guarantees the estimate of the three basic wave characteristics, c, Recrit, a, within the accuracy including O(a3) terms.
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Řešení správy dokumentů ve firmě E-solutions, s.r.o.
Švanda, Jan ; Kunstová, Renáta (advisor) ; Svěžen, Zdeněk (referee)
Presented thesis is focused to the document management system in the firm E-solutions, Ld. Selection of this firm is purposeful, because I have been working in the firm for several years. My thesis is targeted to the complex analysis of document management system (DMS) in the firm and the results of the analysis will be used for the implementation of new DMS. The target is accomplished by following steps, which can be expressed as partial concrete goals: First, the present situation of DMS in the firm is described, next, the detail description of the documents, the system should work with, is presented. Description of these documents is structured to the DMS needs. Subsequently firm processes which should DMS support are identified and analysed. These processes are converted to the optimal conditions to maximize their effectiveness in the DMS support. Integral part of the analysis is the consistent collection of the requirements to the new system. The thesis is divided into theoretical and practical part. The theoretical part describes DMS generally, explains basic principles of DMS (characteristics, documentation and functionality) and creates base line for the practical part. The more comprehensive practical part of the thesis is directed to the document management in the firm E-solutions, Ld. Presentation of the basic information about the firm is followed by detail solution of partial goals. Assessment of the achieved results creates the final part of the work. The thesis will serve in the firm or at a contactor of DMS as the base for the selection, parameterisation and implementation of the concrete DMS solution.
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