Begell House Inc.
International Journal of Fluid Mechanics Research
FMR
2152-5102
45
6
2018
FINITE ELEMENT ANALYSIS OF ROTATING OSCILLATORY MAGNETO-CONVECTIVE RADIATIVE MICROPOLAR THERMO-SOLUTAL FLOW
479-508
MD.
Shamshuddin
Department of Mathematics, Vaagdevi College of Engineering, Warangal, Telangana, India
O. Anwar
Bég
Fluid Mechanics, Nanosystems and Propulsion, Aeronautical and Mechanical Engineering,
School of Computing, Science and Engineering, Newton Building, University of Salford,
Manchester M54WT, United Kingdom
Ali
Kadir
Mechanical/Aeronautical Engineering Department, Newton Building, University of Salford, M5 4WT, UK
Micropolar fluids provide an alternative mechanism for simulating microscale and molecular fluid mechanics, which
require less computational effort. A numerical analysis is conducted for the primary and secondary flow characterizing
dissipative micropolar convective heat and mass transfer from a rotating vertical plate with oscillatory plate velocity adjacent to a permeable medium. Because of high temperature, thermal radiation effects are also studied. The micropolar fluid is also chemically reacting; both thermal and species (concentration) buoyancy effects and heat source/sink are included. The entire system rotates with uniform angular velocity about an axis normal to the plate. Rosseland's diffusion approximation is used to describe the radiative heat flux in the energy equation. The partial differential equations governing the flow problem are rendered dimensionless with appropriate transformation variables. A Galerkin finite element method employed to solve the emerging multiphysical components of a fluid dynamics problem is examined for a variety of parameters, including rotation parameter, radiation-conduction parameter, micropolar coupling parameter, Eckert number (dissipation), reaction parameter, magnetic body force parameter, and Schmidt number. A comparison to previously published work is made to check the validity and accuracy of the present finite element solutions under some limiting cases, and excellent agreement is attained. The current simulations may be applicable to various chemical engineering systems, oscillating rheometry, and rotating MHD energy generator near-wall flows.
ON DYNAMIC AND ENERGY TRANSFER CHARACTERISTICS OF FLOW PAST TRANSVERSELY OSCILLATING CIRCULAR CYLINDER IN THE WAKE OF STATIONARY CYLINDER
509-529
Roam
Simenthy
Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai, India
600036
Vasudevan R.
Raghavan
Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai, India
600036
Shaligram
Tiwari
Department of Mechanical Engineering, Indian Institute of Technology Madras Chennai, India,
600036
Two-dimensional numerical investigations have been carried out to study the flow and energy transfer characteristics
of flow past two inline circular cylinders with a downstream cylinder subjected to forced transverse oscillations. The
effect of transverse oscillations of the downstream cylinder on unsteady wake characteristics as well as exchange of
mechanical energy has been investigated. The dynamic effects, wake behavior, and mechanical energy exchange between the fluid and downstream cylinder have been studied elaborately for different combinations of amplitude, frequency, and inter-cylinder spacing. The oscillation frequency of the downstream cylinder has been varied in the range from 0.4 to 2.0 times the vortex shedding frequency behind a single stationary circular cylinder. Three different values of amplitude, viz., 0.1D, 0.3D, and 0.5D (D being the diameter of either cylinder), have been considered. The spacing between the cylinders (center-to-center distance) is also varied from 2D to 5D for each combination of amplitude and frequency and for fixed value of Reynolds number (Re) equal to 100. Results are presented in the form of vorticity contours, variation of lift and drag coefficients, their signals, and spectra.
EFFECT OF HEIGHT RATIO ON WAKE TRANSITION IN UNSTEADY FLOW PAST ISOSCELES TRAPEZOIDAL CYLINDER
531-552
G. Raghu
Vamsee
Department of Mechanical Engineering, Indian Institute of Technology Madras Chennai, India,
600036
Shaligram
Tiwari
Department of Mechanical Engineering, Indian Institute of Technology Madras Chennai, India,
600036
Thirumalachari
Sundararajan
Thermodynamics and Combustion Engineering
Laboratory Department of Mechanical Engineering
Indian Institute of Technology Madras, Chennai – 600036, India
V.
Raghavan
Department of Mechanical Engineering, Indian Institute of Technology Madras Chennai, India,
600036
Two-dimensional numerical investigations are carried out on flow past a trapezoidal cylinder confined in a channel by
using an indigenously developed finite difference-based flow solver. The solver uses body-fitting coordinate transformation and the marker and cell (MAC) algorithm. Laminar flow of air has been considered past the cylinder of varying height ratio (HR) from 0.2 to 1.0 over a range of Reynolds numbers (Re) from 60 to 200. Effects of HR and Re have been studied on wake and dynamic characteristics for two different orientations of the isosceles trapezoidal cylinder, viz., base facing and apex facing. Critical value of Re for onset of vortex shedding has been identified for both the configurations. Results from the present work illustrate how separation behavior gets modified with change in Re and HR. Also the work aims to find such values of HR that are associated with minimum drag and cause maximum delay in the onset of vortex shedding.
THERMAL DIFFUSION AND JOULE-HEATING EFFECTS ON MAGNETOHYDRODYNAMIC, FREE-CONVECTIVE, HEAT-ABSORBING/-GENERATING, VISCOUS-DISSIPATIVE NEWTONIAN FLUID WITH VARIABLE TEMPERATURE AND CONCENTRATION
553-567
L. Rama Mohan
Reddy
Department of Mathematics, Dr. APJ ABDUL KALAM IIIT, Ongole, Andhra Pradesh, India
M. C
Raju
Jawaharlal Nehru Technological University Anantapur, College of Engineering Pulivendula
P. Chandra
Reddy
Departments of Humanities and Sciences, Annamacharya Institute of Technology and Sciences
(Autonomous), Rajampet, Andhra Pradesh 516126, India
G. S. S.
Raju
Department of Mathematics, JNTUA College of Engineering Pulivendula, Andhra Pradesh,
India
This article presents diffusion-thermo and thermo-diffusion effects on unsteady magnetohydrodynamic, natural-
convection heat and mass-transfer flow past an accelerated vertical porous plate under conditions of thermal radiation,
variable temperature (T), and variable concentration (C). We solve governing equations pertinent to fluid flow by applying finite-difference schemes. Variations in velocity, T, and C are discussed and exhibited with the help of graphs. Numerical values for local skin friction (τ), Nusselt number, and Sherwood number are recorded and analyzed. Increasing values of Soret number (S0) result in augmented C, but C decreases under the influence of the Schmidt number. τ decreases with increasing values of S0.
EFFECT OF WINGLET VARIATION ON UAV AERODYNAMIC CHARACTERISTICS
569-577
Felixtianus Eko Wismo
Winarto
Department of Mechanical Engineering, Vocational School, Universitas Gadjah Mada,
Yogyakarta, Indonesia 55281
Wikan
Sakarinto
Department of Mechanical Engineering, Vocational School, Universitas Gadjah Mada,
Yogyakarta, Indonesia 55281
Setyawan Bekti
Wibowo
Department of Mechanical and Industrial Engineering, Faculty of Engineering, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia; Department of Mechanical Engineering, Vocational College, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
Unmanned aerial vehicle (UAV) performance and stability are largely influenced by design, especially with regard to
wing surface contour flying characteristics. Appropriate aerodynamic character will improve performance and make for
cost-effective fuel consumption and flying stability. One such improvement in aerodynamic character is by the winglet
attachment. The proper winglet addition will improve lift and decrease drag and also produce compact endurance due
to reductions in the wing tip vortex effect. Therefore, winglet attachment has been widely used in commercial aircraft, but rarely in UAV. This research is about improving aerodynamic performance. Better performance for a longer flying time is the first problem in UAV. Increased flying efficiency is produced by winglet configurations rather than by improving the flying time. The experiment begins with a winglet numerical model to decrease the wing tip vortex effect, followed by an aerodynamic flow visualization. In the model, a winglet attachment shows the wing tip vortex effect. The rounded tapered winglet also significantly increases lift force. The highest flight efficiency point on the graph was reached at a 7.5° angle of attraction.
INDEX VOLUME 45
578-584