Egyptian Enlightener Rifa‛a at-Tahtawi

From the 19th c. in Arab countries, first of all, in Egypt, Syria and Lebanon, the political, economic and cultural life begins to revive, which is known as the Revival (the "Nahda"). In this process enlighteners played the crucial role. The aim of the present article is to focus attention on several questions of the world outlook of Rifa‛a at-Tahtawi, the first Egyptian enlightener, in particular, his interpretation of the notions of "homeland" and "nation" and his views on the relationship between the West and the East, on the organization forms of states and societies. In order to demonstrate the question, a brief overview of the viewpoint of the enlighteners (al-Afgani, Abdo, Adib Ishaq, Mustafa Kamil, Farah Antuni, Lufti as-Saidi) and at-Tahtawi is offered. The article also deals with at-Tahtawi's views on problems of women's emancipation, his attitude towards the questions of upbringing and education. In addition, attention is devoted to his views on the notions of "lawfulness", "freedom", "equality", "justice", etc.). At-Tahtawi was the first among the Arabs, if not among the Egyptians, who turned the notion of "citizen" into an object of public discussion and defined the status of "citizen". The study of these questions leads to the conclusion that at-Tahtawi supports the successful achievements and reasonable synthesis of Western and Eastern civilizations, that European science and in general European civilization do not contradict Islam and the Koran. Furthermore, he considers that in his contemporary Europe, France in particular, there develops such a form of the society organization which has long since been known and acceptable to Islam.Enlightener, Rifa‛a at-Tahtawi, homeland, Western and Earstern civilizations

Study of design and analysis methods for transonic flow

An airfoil design program and a boundary layer analysis were developed. Boundary conditions were derived for ventilated transonic wind tunnels and performing transonic windtunnel wall calculations. A computational procedure for rotational transonic flow in engine inlet throats was formulated. Results and conclusions are summarized

Computational methods for vortex dominated compressible flows

The principal objectives were to: understand the mechanisms by which Euler equation computations model leading edge vortex flows; understand the vortical and shock wave structures that may exist for different wing shapes, angles of incidence, and Mach numbers; and compare calculations with experiments in order to ascertain the limitations and advantages of Euler equation models. The initial approach utilized the cell centered finite volume Jameson scheme. The final calculation utilized a cell vertex finite volume method on an unstructured grid. Both methods used Runge-Kutta four stage schemes for integrating the equations. The principal findings are briefly summarized

Multigrid Preconditioning for a Space-Time Spectral-Element Discontinuous-Galerkin Solver

In this work we examine a multigrid preconditioning approach in the context of a high- order tensor-product discontinuous-Galerkin spectral-element solver. We couple multigrid ideas together with memory lean and efficient tensor-product preconditioned matrix-free smoothers. Block ILU(0)-preconditioned GMRES smoothers are employed on the coarsest spaces. The performance is evaluated on nonlinear problems arising from unsteady scale- resolving solutions of the Navier-Stokes equations: separated low-Mach unsteady ow over an airfoil from laminar to turbulent ow. A reduction in the number of ne space iterations is observed, which proves the efficiency of the approach in terms of preconditioning the linear systems, however this gain was not reflected in the CPU time. Finally, the preconditioner is successfully applied to problems characterized by stiff source terms such as the set of RANS equations, where the simple tensor product preconditioner fails. Theoretical justification about the findings is reported and future work is outlined

Analytical investigation of rotor wake formation and geometry

A number of refinements in the computer code were worked out and tested. Three codes have been written to date. One program is for an isolated wing and is being used to compare with data for the vortex wake (Weston). The second code is for an isolated wing with a streamwise vortex passing above it. This program is being used to validate the computational procedure for incorporating the vortex into the Euler equation calculations. The third program is the hovering rotor code which is the overall objective of the research. The optimization calculations for a hovering helicopter rotor have been completed

Finite volume solution of the compressible boundary-layer equations

A box-type finite volume discretization is applied to the integral form of the compressible boundary layer equations. Boundary layer scaling is introduced through the grid construction: streamwise grid lines follow eta = y/h = const., where y is the normal coordinate and h(x) is a scale factor proportional to the boundary layer thickness. With this grid, similarity can be applied explicity to calculate initial conditions. The finite volume method preserves the physical transparency of the integral equations in the discrete approximation. The resulting scheme is accurate, efficient, and conceptually simple. Computations for similar and non-similar flows show excellent agreement with tabulated results, solutions computed with Keller's Box scheme, and experimental data

Aerodynamic design using numerical optimization

The procedure of using numerical optimization methods coupled with computational fluid dynamic (CFD) codes for the development of an aerodynamic design is examined. Several approaches that replace wind tunnel tests, develop pressure distributions and derive designs, or fulfill preset design criteria are presented. The method of Aerodynamic Design by Numerical Optimization (ADNO) is described and illustrated with examples