T. Aldoss | Wichita State University (original) (raw)

Papers by T. Aldoss

JSME International Journal Series B, 1997

Journal of Fluids Engineering, 1988

The rotation of a circular cylinder placed in a uniform flow is assumed to add a circulation to t... more The rotation of a circular cylinder placed in a uniform flow is assumed to add a circulation to the flow around the cylinder proportional to the product of the angular velocity of the cylinder and the front area between upper and lower separation points. Adding the velocity due to this induced circulation to the base velocity distribution of the non-rotating cylinder the new velocity distribution on the rotating cylinder is formed. Thwaites’ method is then used to calculate the laminar boundary layer on the upper and on the lower sides of the cylinder. The stagnation point, and the upper and lower separation points are also calculated at different values of rotational speed. The calculated lift and drag coefficients using a linear pressure distribution on the wake part of the cylinder with the calculated pressure dstribution on the front part between the two separation points show the same trend as the measured values. The torque coefficient is also calculated to estimate the necess...

International Communications in Heat and Mass Transfer, 2004

A steady laminar flow conjugate free convection from a horizontal annulus is investigated. Two ca... more A steady laminar flow conjugate free convection from a horizontal annulus is investigated. Two cases concerning the location of the porous layer were considered. In the first case the porous layer is located adjacent to the inner cylinder. In the second case the porous layer is located adjacent to the outer cylinder. Solution is obtained using a finite volume method. The effect of the p hysical parameters, Grashof number, Darcy number, and porous layer thickness, on the local and average Nusselt number were calculated and presented. Comparison with completely filled with porous media annulus, and with clear fluid case is also presented

International Journal of Heat and Mass Transfer, 1996

Tl~e problem of Non-Darcian mixed convection about a vertical cylinder embedded in a porous mediu... more Tl~e problem of Non-Darcian mixed convection about a vertical cylinder embedded in a porous medium is analyzed. Nonsimilarity solutions are obtained for the case of variable wall temperature (VWT) and variable surface heat flux (VHF).

To reduce the inefficiency and the drawbacks incurred by reheat in a gas turbine engine with the ... more To reduce the inefficiency and the drawbacks incurred by reheat in a gas turbine engine with the two turbines in series, a parallel arrangement is investigated. The combustion gases expand to atmospheric pressure in each turbine. One of the turbines drives the compressor to which it is mechanically coupled while the other develops the power output of the plant. Two

Wind Engineering, 1985

Savonius rotor performance is improved by allowing both downwind and upwind rotor blades to swing... more Savonius rotor performance is improved by allowing both downwind and upwind rotor blades to swing back through an optimum angle. This will minimize the drag on the upwind blade and maximize the drag on the down-wind blade. A combination of 50 degrees upwind blade swing angle and 13.5 degrees downwind blade swing angle have been found experimentally to be the

International Journal of Numerical Methods for Heat & Fluid Flow, 2005

ABSTRACT Purpose – The transient hydrodynamics and thermal behavior of free convection flow over ... more ABSTRACT Purpose – The transient hydrodynamics and thermal behavior of free convection flow over an isothermal vertical flat plate is investigated. Design/methodology/approach – The study focuses on the role of the local acceleration term in the magnetohydrodynamic (MHD) momentum equation. A finite difference method based on a second-order differential equation is used to solve the differential equations. Findings – It is found that the local acceleration term has insignificant effect on the flow behavior especially at large values of magnetic forces. Also, it is found that the effect of the magnetic forces on the flow hydrodynamics behavior is significant but its effect on the thermal behavior is insignificant. It has been realized that the local acceleration term is usually small compared to the magnetic retarding force, and hence can be neglected. Research limitations/implications – A quantitative description of the operating and geometrical parameters within which the local acceleration term may be significant is not available in the literature yet. Also, the authors' intention is to improve physical understanding of the hydrodynamic and thermal behaviors of the present problem. Originality/value – The study provides results concerning the thermal behavior of free convection flow.

Aircraft Engineering and Aerospace Technology, 1994

If you would like to write for this, or any other Emerald publication, then please use our Emeral... more If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information.

Numerical Heat Transfer, Part A: Applications, 1995

Magnetohydrodynamic mixed convection flaw about a vertical flat plate embedded in a porous medium... more Magnetohydrodynamic mixed convection flaw about a vertical flat plate embedded in a porous medium is considered. The effect of the magnetic field strength on the local Nusselt number and local wait shear stress is presented. The non-Darcian model including both the inertia and boundary effects is used. A particular transformation for the governing equations is adopted to cover the whole

Numerical Heat Transfer, Part A: Applications, 1994

ABSTRACT

Numerical Heat Transfer, Part A: Applications, 1996

... TK Aldoss,Y.D. Ali, and MA Al-Nimr MechanicalEngineering Department, Jordan University of Sci... more ... TK Aldoss,Y.D. Ali, and MA Al-Nimr MechanicalEngineering Department, Jordan University of Scienceand Technology, Irbid; Jordan ... Recently, Hossain and Ahmed [4] studied the combined effect of forced and free convection boundary layer flow near the leading edge of a ...

Journal of Porous Media, 2005

Journal of Enhanced Heat Transfer, 2004

... Using Capsulated Liquid Metal Fins for Heat Transfer Enhancement. Taha K. Aldoss Mechanical E... more ... Using Capsulated Liquid Metal Fins for Heat Transfer Enhancement. Taha K. Aldoss Mechanical Engineering Department, Jordan University of Science and Technology, Irbid 22110, Jordan. Moh'd Ahmad Al-Nimr Jordan University of Science and Technology. ABSTRACT. ...

International Journal of Heat and Mass Transfer, 1993

Nonsimilarity solutions for mixed convection from a vertical Rat plate embedded in a porous mediu... more Nonsimilarity solutions for mixed convection from a vertical Rat plate embedded in a porous medium are reported for two surface heating conditions: variable wall temperature (VWT) and variable surface heat flux (VHF) of the power-law form. The entire mixed convection regime is divided into two regions. One region covers the forced convection dominated regime and the other one covers the free convection dominated regime. The governing equations are first transformed into a dimensionless form by the nonsimilar transformation and then solved by a finite-difference scheme. Four nonsimilarity parameters are introduced. The parameters Ra,/Pe, and Ra:/Pe: ' characterize the effect of buoyancy forces on the forced convection for the VWT and VHF cases, respectively; while the parameters Pe,/Ru, and Pr,/Ra:"' characterize the effect of forced flow on the free convection for VWT and VHF cases, respectively. Numerical results for both heating conditions are presented. Correlation equations for the local and average Nusselt numbers are also presented.

International Journal of Heat and Fluid Flow, 1996

An experimental investigation of a conical flow formed by the interaction of two asymmetric turbu... more An experimental investigation of a conical flow formed by the interaction of two asymmetric turbulent curved wall jets past a circular cone is presented. Measurements were made of velocity and turbulence intensity profiles of the two jets in the wall jet, the interaction, and the merged jet regions. The location of the interaction region of the two opposing curved wall jets and the flow direction of the merged jet were found to depend primarily on the ratio of the slot exit velocities of the two jets. The mean velocity and streamwise turbulence intensity profiles of the merged jet were similar to those in a turbulent free jet. Regardless of jet-exit velocity ratios, self-similar mean velocity profiles for different values of downstream location prevails up to the beginning of interaction region. The streamwise and lateral turbulence intensities increase with increasing the streamwise distance up to the interaction region, where the turbulence behavior becomes random and is characterized by larger peak values of the turbulence intensity compared to wall jet region. The maximum velocity decay and jet half-width growth increased parabolically with streamwise distance. No significant effect of conical shape was observed. Surface flow visualization was carried out for several exit jet velocity ratios. Three dimensionality was seen to be reduced as the secondary jet momentum increases.

Applied Scientific Research, 1991

Pressure drop measurements in the laminar and turbulent regions for water flowing through an alte... more Pressure drop measurements in the laminar and turbulent regions for water flowing through an alternating curved circular tube (x = h sin 2nz/2) are presented. Using the minimum radius of curvature of this curved tube in place of that of the toroidally curved one in calculating the Dean number (ND = Re(D/2Rc) 2, it is found that the resulting Dean number can help in characterizing this flow. Also, the ratio between the height and length of the tube waves which represents the degree of waveness affects significantly the pressure drop and the transition Dean number. The following correlations have been found:

Experimental Thermal and Fluid Science, 1990

IIThis paper presents the results for an experimental investigation of the flow pattern around a ... more IIThis paper presents the results for an experimental investigation of the flow pattern around a rotating cylinder placed in a crossflow air stream. The velocity profiles upstream and downstream of the cylinder, skin friction coefficient, stagnation, and separation points are obtained for different rotation speed ratios (~ = QRN~) varying from 0.0 to 1.25. Compared to the non-rotating cylinder in crossflow, it was found that the position of the stagnation point for the rotating cylinder is a strong function of the rotational speed; however, the separation points are only slightly dependent on such speed. This investigation indicates also that the skin friction dominates on the upstream moving-wall of the cylinder. Concerning the flow behind the rotating cylinder the measurements indicate that the wake behind the cylinder is asymmetric; for example, it is shifted in the direction of rotation and its axial length and width becomes smaller for the considered rotation speed ratios. For the flow ahead a slight effect of rotation is noticed. Some of the results obtained here are compared with a simple theoretical model [1] and the comparison shows fair agreement.

Heat and Mass Transfer, 1997

Non-Darcy mixed convection in a porous medium from horizontal surfaces with variable surface heat... more Non-Darcy mixed convection in a porous medium from horizontal surfaces with variable surface heat flux of the power-law distribution is analyzed. The entire mixed convection regime is divided into two regions. The first region covers the forced convection dominated regime where the dimensionless parameter ζ f =Ra* x /Pe2 x is found to characterize the effect of buoyancy forces on the forced convection with K ′ U ∞/ν characterizing the effect of inertia resistance. The second region covers the natural convection dominated regime where the dimensionless parameter ζ n =Pe x /Ra*1/2 x is found to characterize the effect of the forced flow on the natural convection, with (K ′ U ∞/ν)Ra*1/2 x /Pe x characterizing the effect of inertia resistance. To obtain the solution that covers the entire mixed convection regime the solution of the first regime is carried out for ζ f =0, the pure forced convection limit, to ζ f =1 and the solution of the second is carried out for ζ n =0, the pure natural convection limit, to ζ n =1. The two solutions meet and match at ζ f =ζ n =1, and R * h =G * h . Also a non-Darcy model was used to analyze mixed convection in a porous medium from horizontal surfaces with variable wall temperature of the power-law form. The entire mixed convection regime is divided into two regions. The first region covers the forced convection dominated regime where the dimensionless parameter ξ f =Ra x /Pe x 3/2 is found to measure the buoyancy effects on mixed convection with Da x Pe x /ɛ as the wall effects. The second region covers the natural convection dominated region where ξ n =Pe x /Ra x 2/3 is found to measure the force effects on mixed convection with Da x Ra x 2/3/ɛ as the wall effects. Numerical results for different inertia, wall, variable surface heat flux and variable wall temperature exponents are presented.