The performance of fluid pumps based on  Wankel-type geometry, taking the shape of a double-lobed lima&#xe7;on, is characterized. To the authors&#x2019; knowledge, this is the first time such an attempt has been made. To this end, numerous simulations for three different pump sizes were carried out and the results were understood in terms of the usual scaling coefficients. The results show that such pumps operate as low efficiency (&#x3c;30&#x25;) valveless positive displacements pumps, with pump flow-rate noticeably falling at the onset of internal leakage. Also, for such pumps, the mechanical efficiency varies linearly with the head coefficient, and, within the onset of internal leakage, the capacity coefficient holds steady even across pump efficiency. Simulation of the flow field reveals a structure rich in three-dimensional vortices even in the laminar regime, including  Taylor-like counterrotating vortex pairs, pointing  towards the utility of these pumps in microfluidic applications. Given the planar geometry of such pumps, their applications as microreactors and micromixers are recommended.

Stephen Wan

Jason Leong

Te Ba

Arthur Lim

Chang Wei Kang

Numerical Characterization of the Performance of Fluid Pumps Based on a Wankel Geometry

The flow distribution in manifolds is highly dependent on inlet pressure, configuration, and total inlet flow to the manifold. The flow from a manifold has many applications and in various fields of engineering such as civil, mechanical, and chemical engineering. In this study, physical and numerical models were employed to study the uniformity of the flow distribution from manifold with various configurations. The physical model consists of main manifold with uniform longitudinal section having diameter of 10.16&#x2009;cm (4&#x2009;in), five laterals with diameter of 5.08&#x2009;cm (2&#x2009;in), and spacing of 22&#x2009;cm. Different inlet flows were tested and the values of these flows are 500, 750, and 1000&#x2009;L/min. A manifold with tapered longitudinal section having inlet diameters of 10.16&#x2009;cm (4&#x2009;in) and dead end diameter of 5.08&#x2009;cm (2&#x2009;in) with the same above later specifications and flow rates was tested for its uniformity too. The percentage of absolute mean deviation for manifold with uniform diameter was found to be 34&#x25; while its value for the manifold with nonuniform diameter was found to be 14&#x25;. This result confirms the efficiency of the nonuniform distribution of fluids.

Jafar M. Hassan

Thamer A. Mohamed

Wahid S. Mohammed

Wissam H. Alawee

Modeling the Uniformity of Manifold with Various Configurations

Double diffusive convection in a horizontal layer of Maxwell viscoelastic fluid in a porous medium in the presence of temperature gradient (Soret effects) and concentration gradient (Dufour effects) is investigated. For the porous medium Darcy model is considered. A linear stability analysis based upon normal mode technique is used to study the onset of instabilities of the Maxwell viscolastic fluid layer confined between two free-free boundaries. Rayleigh number on the onset of stationary and oscillatory convection has been derived and graphs have been plotted to study the effects of the Dufour parameter, Soret parameter, Lewis number, and solutal Rayleigh number on stationary convection.

Ramesh Chand

G. C. Rana

Double Diffusive Convection in a Layer of Maxwell Viscoelastic Fluid in Porous Medium in the Presence of Soret and Dufour Effects

A multidimensional diffusion flux mixture model was developed to simulate water jet two-phase flows. Through the modification of the gravity using the gradients of the mixture velocity, the centrifugal force on the water droplets was able to be considered. The slip velocities between the continuous phase (gas) and the dispersed phase (water droplets) were able to be calculated through multidimensional diffusion flux velocities based on the modified multidimensional drift flux model. Through the numerical simulations, comparing with the experiments and the simulations of traditional algebraic slip mixture model on the water mist spray, the model was validated.

Zhi Shang

Jing Lou

Hongying Li

Numerical Simulation of Water Jet Flow Using Diffusion Flux Mixture Model

The paper presents a numerical investigation of non-Newtonian modeling effects on unsteady periodic flows in a two-dimensional (2D) pipe with two idealized stenoses of 75&#x25; and 50&#x25; degrees, respectively. The governing Navier-Stokes equations have been modified using the Cartesian curvilinear coordinates to handle complex geometries. The investigation has been carried out to characterize four different non-Newtonian constitutive equations of blood, namely, the (i) Carreau, (ii) Cross, (iii) Modified Casson, and (iv) Quemada models. The Newtonian model has also been analyzed to study the physics of fluid and the results are compared with the non-Newtonian viscosity models. The numerical results are represented in terms of streamwise velocity, pressure distribution, and wall shear stress (WSS) as well as the vorticity, streamlines, and vector plots indicating recirculation zones at the poststenotic  region. The results of this study demonstrate a lower risk of thrombogenesis at the downstream of stenoses and inadequate blood supply to different organs of human body in the Newtonian model compared to the non-Newtonian ones.

Mir Golam Rabby

Sumaia Parveen Shupti

Md. Mamun Molla

Pulsatile Non-Newtonian Laminar Blood Flows through Arterial Double Stenoses

An analysis is carried out to study the steady two-dimensional flow of an incompressible viscous fluid past a porous deformable sheet, which is stretched in its own plane with a velocity proportional to the distance from the fixed point subject to uniform suction or blowing. A uniform shear flow of strain rate <i>&#x3b2;</i> is considered over the stretching sheet. The analysis of the result obtained shows that the magnitude of the wall shear stress increases with the increase of suction velocity and decreases with the increase of blowing velocity and this effect is more pronounced for suction than blowing. It is seen that the horizontal velocity component (at a fixed streamwise position along the plate) increases with the increase in the ratio of shear rate <i>&#x3b2;</i> and stretching rate (<i>c</i>) (i.e., <i>&#x3b2;</i>/<i>c</i>) and there is an indication of flow reversal. It is also observed that this flow reversal region increases with the increase in <i>&#x3b2;</i>/<i>c</i>.

Samir Kumar Nandy

Swati Mukhopadhyay

Viscous Flows Driven by Uniform Shear over a Porous Stretching Sheet in the Presence of Suction/Blowing

Stability of thermal convection in an infinitely long vertical channel in the presence of a uniform horizontal magnetic field applied in the direction parallel to the hot and cold walls was numerically studied. First, in order to confirm accuracy of the present numerical code, the one-dimensional computations without the effect of magnetic field were computed and they agreed with a previous study quantitatively for various values of the Prandtl number. Then, linear stability analysis for the thermal convection flow in a square horizontal cross section under the magnetic field was carried out for the case of Pr = 0.025. The thermal convection flow was once destabilized at certain low Hartmann numbers, and it was stabilized at high Hartmann numbers.

Takashi Kitaura

Toshio Tagawa

Linear Stability Analysis of Thermal Convection in an Infinitely Long Vertical Rectangular Enclosure in the Presence of a Uniform Horizontal Magnetic Field

This paper is devoted to the study of the peristaltic motion of non-Newtonian fluid with heat and mass transfer through a porous medium in the channel under the effect of magnetic field. A modified Casson non-Newtonian constitutive model is employed for the transport fluid. A perturbation series&#x2019; method of solution of the stream function is discussed. The effects of various parameters of interest such as the magnetic parameter, Casson parameter, and permeability parameter on the velocity, pressure rise, temperature, and concentration are discussed and illustrated graphically through a set of figures.

Nabil T. M. Eldabe

Bothaina M. Agoor

Heba Alame

Peristaltic Motion of Non-Newtonian Fluid with Heat and Mass Transfer through a Porous Medium in Channel under Uniform Magnetic Field

Impinging jet heat transfer on a target plate was enhanced by using two parallel confining
plates mounted between a rectangular nozzle end plate and a jet target plate. The target
plate was set equal to 2, 3, 4, and 5 times the jet exit width, <svg     style="vertical-align:-0.1638pt;width:8.8999996px;" id="M1" height="12.4375" version="1.1" viewBox="0 0 8.8999996 12.4375" width="8.8999996"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
			<g transform="matrix(.017,-0,0,-.017,.062,12.162)"><path id="x210E" d="M499 88q-41 -46 -83.5 -73t-68.5 -27q-41 0 -19 98l52 225q10 43 8 59.5t-16 16.5q-37 0 -112 -65t-117 -135q-14 -42 -38 -179q-36 -7 -75 -20l-7 8l127 594q8 40 2.5 49t-35.5 9h-35l5 25q36 3 71.5 13t56.5 18t25 8q11 0 3 -38l-88 -417h2q77 102 195 167q44 24 79 24&#xA;q61 0 30 -130l-52 -220q-8 -33 4 -33q8 0 31 14.5t43 33.5z" /></g>

		
	
</svg>, and the gap ratio of two parallel confining plates, <svg     style="vertical-align:-2.22495pt;width:33.174999px;" id="M2" height="15" version="1.1" viewBox="0 0 33.174999 15" width="33.174999"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
			<g transform="matrix(.017,-0,0,-.017,.062,12.162)"><path id="x1D44A" d="M1004 650l-6 -29q-54 -6 -71 -19.5t-51 -74.5l-271 -539h-33l-98 506h-3l-258 -506h-30l-78 532q-10 67 -21.5 80t-66.5 21l6 29h241l-8 -29l-26 -5q-34 -6 -41 -16t-3 -47l59 -425h4l251 510h31l102 -510h2q150 299 198 423q14 40 8.5 48.5t-47.5 16.5l-28 5l7 29h231z&#xA;" /></g><g transform="matrix(.017,-0,0,-.017,17.333,12.162)"><path id="x2F" d="M368 703l-264 -866h-60l265 866h59z" /></g><g transform="matrix(.017,-0,0,-.017,24.337,12.162)"><use xlink:href="#x210E"/></g>

		
	
</svg>, were changed from 2.7 to 8.0 only by impinging length <svg     style="vertical-align:-0.1638pt;width:51.387501px;" id="M3" height="12.4375" version="1.1" viewBox="0 0 51.387501 12.4375" width="51.387501"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
			<g transform="matrix(.017,-0,0,-.017,.062,12.162)"><path id="x1D43B" d="M865 650q-1 -4 -4 -14t-4 -14q-62 -5 -77 -19.5t-29 -82.5l-74 -394q-12 -61 -0.5 -77t75.5 -21l-6 -28h-273l8 28q64 5 82 21t29 76l36 198h-380l-37 -197q-11 -64 0.5 -78.5t79.5 -19.5l-6 -28h-268l6 28q60 6 75.5 21.5t26.5 76.5l75 394q13 66 2 81.5t-77 20.5l8 28&#xA;h263l-6 -28q-58 -5 -75.5 -21t-30.5 -81l-26 -153h377l29 153q12 67 2 81t-74 21l5 28h268z" /></g><g transform="matrix(.017,-0,0,-.017,19.679,12.162)"><path id="x3D" d="M535 323h-483v50h483v-50zM535 138h-483v50h483v-50z" /></g><g transform="matrix(.017,-0,0,-.017,34.383,12.162)"><path id="x35" d="M153 550l-26 -186q79 31 111 31q90 0 141.5 -51t51.5 -119q0 -93 -89 -166q-85 -69 -173 -71q-32 0 -61.5 11.5t-41.5 23.5q-18 17 -17 34q2 16 22 33q14 9 26 -1q61 -50 124 -50q60 0 93 43.5t33 104.5q0 69 -41.5 110t-121.5 41q-53 0 -102 -20l38 305h286l6 -8&#xA;l-26 -65h-233z" /></g><g transform="matrix(.017,-0,0,-.017,42.542,12.162)"><use xlink:href="#x210E"/></g>

		
	
</svg> and from 2.7 to 6.7 by <svg     style="vertical-align:-1.35135pt;width:47.612499px;" id="M4" height="13.9125" version="1.1" viewBox="0 0 47.612499 13.9125" width="47.612499"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
			<g transform="matrix(.017,-0,0,-.017,.062,12.162)"><use xlink:href="#x1D43B"/></g><g transform="matrix(.017,-0,0,-.017,17.792,12.162)"><path id="x2260" d="M535 138h-247l-72 -237l-55 17l67 220h-176v50h192l41 135h-233v50h248l73 237l54 -17l-67 -220h175v-50h-190l-41 -135h231v-50z" /></g><g transform="matrix(.017,-0,0,-.017,30.609,12.162)"><use xlink:href="#x35"/></g><g transform="matrix(.017,-0,0,-.017,38.769,12.162)"><use xlink:href="#x210E"/></g>

		
	
</svg>. Two confining parallel plates mounted near the jet exit produced
swing-type flow under some conditions. As a result, the maximum Nusselt number
attained around the stagnation point was augmented by about 50&#x25; compared to the one
for normal impinging jet without the two parallel plates and then spatial mean Nusselt
number was increased by about 40&#x25;.

Yoshiaki Haneda

Akiko Souma

Hideo Kurasawa

Shouichiro Iio

Toshihiko Ikeda

Enhancement of Impinging Jet Heat Transfer Using Two Parallel Confining Plates Mounted near Rectangular Nozzle Exit

An investigation is made on the effect of suspended particles (fine dust) on double-diffusive convection of a compressible Rivlin-Ericksen elastico-viscous fluid. The perturbation equations are analyzed in terms of normal modes after linearizing the relevant set of equations. A dispersion relation governing the effects of viscoelasticity, compressibility, stable solute gradient, and suspended particles is derived. For stationary convection, Rivlin-Ericksen fluid behaves like an ordinary Newtonian fluid due to the vanishing of the viscoelastic parameter. The stable solute gradient compressibility has a stabilizing effect on the system whereas suspended particles hasten the onset of thermosolutal instability. The Rayleigh numbers and the wave numbers of the associated disturbances for the onset of instability as stationary convection are obtained and the behaviour of various parameters on Rayleigh numbers has been depicted graphically. It has been observed that oscillatory modes are introduced due to the presence of viscoelasticity, suspended particles, and stable solute gradient which were not existing in the absence of these parameters.

Mahinder Singh

Rajesh Kumar Gupta

Double-Diffusive Convection in Presence of Compressible Rivlin-Ericksen Fluid with Fine Dust

Hydraulic analysis of water distribution networks is an important problem in civil engineering. A widely used approach in steady-state analysis of water distribution networks is the global gradient algorithm (GGA). However, when the GGA is applied to solve these networks, zero flows cause a computation failure. On the other hand, there are different mathematical formulations for hydraulic analysis under pressure-driven demand and leakage simulation. This paper introduces an optimization model for the hydraulic analysis of water distribution networks using a metaheuristic method called shuffled complex evolution (SCE) algorithm. In this method, applying if-then rules in the optimization model is a simple way in handling pressure-driven demand and leakage simulation, and there is no need for an initial solution vector which must be chosen carefully in many other procedures if numerical convergence is to be achieved. The overall results indicate that the proposed method has the capability of handling various pipe networks problems without changing in model or mathematical formulation. Application of SCE in optimization model can lead to accurate solutions in pipes with zero flows. Finally, it can be concluded that the proposed method is a suitable alternative optimizer challenging other methods especially in terms of accuracy.

Naser Moosavian

Mohammad Reza Jaefarzadeh

Hydraulic Analysis of Water Distribution Network Using Shuffled Complex Evolution

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Journal of Fluids