Zagazig University Digital Repository
Home
Thesis & Publications
All Contents
Publications
Thesis
Graduation Projects
Research Area
Research Area Reports
Search by Research Area
Universities Thesis
ACADEMIC Links
ACADEMIC RESEARCH
Zagazig University Authors
Africa Research Statistics
Google Scholar
Research Gate
Researcher ID
CrossRef
Group Transformation Theory Applied to The Solution of Partial Differential Equations
Faculty
Engineering
Year:
2009
Type of Publication:
Theses
Pages:
135
Authors:
Ahmed Saad Rashed Rashed
BibID
10801836
Keywords :
Differential equations
Abstract:
The application of the group method in this thesis to different physical problems; two boundary layer problems and a wave problem, proved its ability in reducing nonlinear partial differential equations to ordinary ones. During the last steps of reduction the initial or boundary conditions were algebraically deduced. The most important results obtained are summarized in the following paragraphs. In the first application; 1- Two types of similarity transformations are obtained; A translational transformation η= y (α1x + β1)m and a helical one η= y erx. The boundary condition; c0(x) isanalytically evaluated and not assumed as for example Anderson et al [4], Birkhoff [94] and Gebhart [92] works. The obtained boundary conditions match the physical boundary conditions. 2- A relation between ‘m’ and ‘n’ was analytically deduced in chapter-3 in the form; where ‘m’; the transformation ratio relating ‘x’ to ‘y’ , n is the reaction order. This relation is new and physically means that the similarity transformation of y with respect x is bounded by the reaction order n. 3- The numerical solution proved that the greater the Schmidt number, the less the maximum velocity attained by the fluid and the thinner the concentration layer. This is due to the decrease in the molecular diffusivity of the fluid which results in the previous behaviour.In the second application; 1- The concentration of species next to the wall was analytically derived 2- The numerical results show that the greater the Schmidt number, the less the maximum velocity attained by the fluid and the thinner the concentration layer. This is due to the decrease in the molecular diffusivity of the fluid and the reduction of the buoyancy effect.3- The perturbation analysis about the singularity, n=1, gives an approximate analytical solution comparable with the numerical solution .In the third application; 1- Two similarity variables on the form; and are obtained. Both cases are new and differ from the usual assumption η= x-ct used in the exact solution of Hirota-Satsuma KdV problems 2- m =-3 is deduced analytically and implies that α2=3 α1 i.e. the amplitude time factor equal three times the x amplification factor. This result is compatible with transformations of KdV equations. 3- The initial conditions for ‘u’ and ‘v’ were derived analytically and found functions of (α1x.+β1)-2. This result corresponds to the group transformation of and described in (5.18). 6.2 Conclusions from the previous results, the group method proved that it’s an effective way to get similarity solutions for both boundary and initial value problems and to release new solutions that had never been obtained by other methods. Also, it can get comparable results with miscellaneous methods in the field.
PDF
جامعة المنصورة
جامعة الاسكندرية
جامعة القاهرة
جامعة سوهاج
جامعة الفيوم
جامعة بنها
جامعة دمياط
جامعة بورسعيد
جامعة حلوان
جامعة السويس
شراقوة
جامعة المنيا
جامعة دمنهور
جامعة المنوفية
جامعة أسوان
جامعة جنوب الوادى
جامعة قناة السويس
جامعة عين شمس
جامعة أسيوط
جامعة كفر الشيخ
جامعة السادات
جامعة طنطا
جامعة بنى سويف