آزاد تجارت کے فوائد و نقصانات

On the one hand Islam espouses the notion of free trade, and on the other hand it frowns on state interference in trade. Developed and developing countries make head way freely in a free trading culture. This state of affairs buoys up the spirits of traders and inspires them to invest freely and lead to an economic upturn. Thus society flourishes. Foreign direct investment flows in a country from free trade. The scientificand technical expertise of industrialized countries is transferred to low income countries. Not only high quality products are available in abundance in the open market but also the moderation of prices is automatically established by the competition of business people. In this way, the free trading culture functions as a filtering device in the free market and,  without any artificial or external interference, discharges all the tasks efficiently from its own internal logic. Critics of free trade, on the other hand, demur the system fills the coffers of multinational corporations but suppresses the rights of workers,  locals and small industrialists. The real purpose of this system is to establish Western powers’ control over global resources. Taking advantage of the flexibility of the free trading culture,  traders artificially raise prices through monopoly and hoarding.

Numerical Study of a Few Problems for Steady and Incompressible Flows of Micropolar Fluids

The present research work is the numerical study of some problems in micropolar fluids flow. The micropolar fluids are viscous fluids having five additional coefficients of viscosity as compared to usual Newtonian fluids. In the micropolar fluid theory, in addition to the usual classical field of velocity, there are two supplementary field variables, the micro-rotation ν (or spin) and the gyration parameter j which have been introduced to elucidate the kinematics of micro-motions. A micropolar fluid contains rotating micro-constituents that cause the fluid to exhibit non-Newtonian behavior. Micropolar fluid model has been found useful in the study of flows of exotic lubricants, colloidal suspensions, polymeric fluids, liquid crystals, additive suspensions, body fluids, turbulent shear flows and flows in capillaries and micro channels. The study investigates the numerical solution of a few problems for steady, laminar and incompressible flow of both the micropolar fluids and Newtonian fluids. The body couples are neglected in case of micropolar fluids flow. The similarity transformations have been used to reduce the governing partial differential equations of motion in to ordinary differential equations. The resulting boundary value problems have been solved by using appropriate numerical techniques. The central differences are applied to these differential equations. The difference equations thus obtained are solved by using Successive Over Relaxation (SOR) method and Simpson’s (1/3) rule. The numerical results have been shown both in tabular as well as in graphical forms. To obtain accuracy of the present numerical results, the computation has been carried out on three different grid sizes. The purpose of this study is to present the numerical solution of different types of flow problems in micropolar fluids as well as in computational fluid dynamics by using appropriate numerical techniques which are straightforward, easy to program and economical. It has been concluded that our numerical scheme works well to solve various flow problems of Newtonian and micropolar fluids. Moreover, the present results of both Newtonian and micropolar fluids are calculated up to six decimal place. The corresponding results of Newtonian fluids for each problem considered have been obtained and presented for comparison purposes.