In this paper, the application of the surface mass transfer optimization in shock wave-boundary layer interaction control at off-design conditions of transonic aircraft wing is presented. The suction or injection parameters include for example its position on the airfoil, its angle, the length of the hole and the rate of the injected or sucked flow. The optimization process is carried out using an efficient Genetic Algorithm (GA) method. The compressible viscous flow equations in Reynolds Averaged form are solved together with a twoequation k-epsilon turbulence model to accurately compute the objective function. Four different objective functions are introduced including maximum lift to drag ratio, minimum drag coefficient, maximum lift to drag ratio with no drag increment and minimum drag coefficient with no lift decrement. Effectiveness of each objective function is examined by comparing the optimum results in terms of the flow control parameters and flow characteristics.

The problem of unsteady Stokes flow of certain Newtonian fluids in a circular pipe of uniform cross section is discussed. The pipe is uniformly porous. The unsteady Navier-Stokes equations for the system in cylindrical polar coordinates have been solved analytically to obtain a complete description of the flow. The solution of the flow equations subject to the slip boundary conditions leads to the detailed expressions for axial and radial components of velocity and the pressure distribution depending on position coordinates and time. As a special case we have presented the situation when no-slip boundary conditions are implemented. The velocity profile is analyzed for different values of the flow parameters like Womersley number, slip length and time.

Dear editor, suction syringes are utilized to produce blisters for epidermal grafts, as well as for treating localized and stable vitiligo with better cosmetic acceptability. However, the suction process should be fast to save time. The 3-way cannulasyringe can produce blisters within 1 to 2 h (1). Moreover, the failure of this device at-300 to-400mmHg to produce a suction blister and the incidence of incomplete blisters at the site are seen in about 20 to 30% of cases (2, 3). The success rate is improved by the application of heat, intralesional injection of normal saline and local anesthetic agents over the donor site. Thus, the 3-way cannula-syringe is a little cumbersome and time-consuming device...

In this study, the micropolar fluid flow conveyed through suction or injection in a non-Darcy porous medium with high mass transfer is considered. The micropolar fluid flow is described by coupled systems of higher order, ordinary, nonlinear differential equations. Therefore the variation of parameters method is utilized in generating analytical solutions to the mathematical models arising from flow and rotation of the micropolar fluid. As the variation of parameters method is a relatively easy, yet efficient approach of analyzing both strongly and weakly dependent nonlinear equations with a rapid convergence rate. Pertinent rheological fluid parameter effects such as non-Darcy parameter and Reynolds number on flow and rotation are examined using the obtained analytical solutions. Observations from graphical representation of result illustrate flow increase during injection and slight radial velocity decrease for suction flow. Reynolds parameter effect on fluid particles micro rotation also shows decrease in rotation profile during injection while during suction increased particle rotation is observed as a result of high mass transfer. Results obtained from study compared against existing works in literature prove to be in satisfactory agreement. Therefore this paper can be used to further study of micropolar fluids applications such as blood flow, lubricants and micro channel flows amongst others.

A numerical model was developed to simulate the transport phenomena of a flow between two parallel plates with one porous and one non-porous (or impermeable) wall. The continuity and momentum equations were solved first, assuming the suction or injection is uniform and wall Reynolds number is in the range -5£Rew£+5. The results show that at a constant inlet and wall Reynolds number, the friction factor on the porous wall with suction was bigger than that with injection, but the axial non-dimensional pressure drop with injection was larger than the pressure drop in the fully developed flow between impermeable plates and also larger than the pressure drop with suction. This is because of the net increase of the mean velocity of flow along the channel when injection is imposed. In the presence of suction the pressure drop is controlled by the suction rate and approaches a constant value as the inertia and viscous forces are counterbalanced in the flow. The energy equationwas solved independently assuming a constant suction or injection rate of air in the porous wall using different thermal boundary conditions. The results show that the Nusselt number distribution along the channel depends on the thermal boundary conditions imposed on porous and non-porous walls. The thermal characteristics also depend on whether suction or injection occurs through the porous wall.

Control of a fluid flow velocity profile by injection and suction of a non-ionized fluid in presence of a uniform steady magnetic field has important technical applications. In this paper, the unsteady incompressible and viscous conducting fluid flow has been investigated in a circular channel. The channel walls are assumed to be non-conducting and porous. They are subjected to a uniform steady magnetic field which is perpendicular to the axis of channel, then and suction and injection are applied at the walls. The well known equations of Magneto hydrodynamics are governed to the motion of an electrically conducting fluid flow that is subjected to magnetic field. The numerical solution is carried out by finite difference approach. The results of present numerical simulation shown that the flow injection and suction through the wall can be controlled effectively, the main flow in channel especially in industrial purposes. The results are obtained for different values of the injected and sucked non-ionized flow rate and the effect of Hartman number on the velocity profile is investigated. Finally, a good agreement is seen between the presented results and the corresponding data of finite element method.

The effects of uniform injection and suction through the surfaces of a perforated square cylinder on the vortex shedding, heat transfer and some aerodynamic parameters have been investigated numerically. The finite-volume method has been used for solving the Navier-Stokes equations for incompressible and turbulent near-wake flow (𝑅 𝑒  21400) with the k-ɛ turbulence model equations. To find the optimum conditions, the effects of injection and suction through the front surface (case Ⅰ ), the rear surface (case Ⅱ ), top-bottom surfaces (case Ⅲ ) and all surfaces (case Ⅳ ) with various injection/suction coefficient  are studied. The results reveal that parameters such as pressure and drag coefficients and Nusselt number are influenced drastically in some cases as well as flow field parameters. For instance, the maximum reduction of the drag coefficient occurs at case Ⅳ while the maximum increase and reduction of Nu number occur at (|𝛤 |)=0. 025 for all cases about 46% and 32%, 61% and 63%, 92% and 60% and 180% and 115% for cases Ⅰ , Ⅱ , Ⅲ and Ⅳ respectively.

The unsteady mixed convection flow within a vertical concentric cylindrical annulus with time-dependent moving walls is investigated. Fluid is suctioned/injected through the cylinder walls of the annulus. The effects of wall movement on flow and heat transfer characteristics inside the cylindrical annulus are sought. An exact solution of Navier-Stokes and energy equations is obtained in this problem, for the fi rst time. Here, the heat transfer occurs from the walls of the hot cylinder with constant temperature to the moving fluid with a cooling role. It is interesting to note that the results indicate that the time-dependency of cylinder wall movements has no effect on the temperature pro le. The results also indicate that usage of an inverse of time for velocity movement causes a signifi cant increase in velocity, stress tensor, and Nusselt number in the vicinity of the moving wall. Also, increasing the mixed convection and suction/injection parameters increases the Nusselt number and decreases the stress tensor on the inner and outer cylinders, respectively; no matter what velocity function is chosen for the moving wall. Therefore, using the velocity function of the wall movement and the change in other nondimensional governing parameters, flow and heat transfer can be controlled.