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CONTENTS
Volume 28, Number 6, June 2019
 

Abstract
This study provides an approximate analytical solution to the fractional vibration problem of thin plate governing anomalous motion of plate subjected to in-plane loads. The method of variable separable is employed to transform the fractional partial differential equations under consideration into a fractional ordinary differential equation in temporal variable and a bi-harmonic plate equation in spatial variable. The technique of conformable fractional derivative is utilized to solve the resulting fractional differential equation and the approach of finite sine integral transform method is used to solve the accompanying bi-harmonic plate equation. The deflection field which measures the transverse displacement of the plate is expressed in terms of product of Bessel and trigonometric functions via the temporal and spatial variables respectively. The obtained solution reduces to the solution of the free vibration problem of thin plate in literature. This work shows that conformable fractional derivative is an efficient mathematical tool for tracking analytical solution of fractional partial differential equation governing anomalous vibration of thin plates.

Key Words
conformable solution; fractional vibration; in-plane loads; thin plate

Address
Odunayo O. Fadodun, Olawanle P. Layeni and Adegbola P. Akinola: Department of Mathematics, Obafemi Awolowo University, Ile-Ife, 220005, Nigeria
Babafemi O. Malomo: Department of Mechanical Engineering, Obafemi Awolowo University, 220005, Nigeria

Abstract
Control of horseshoe vortex in the circular cylinder-plate juncture using vortex generator (VG) was studied at ReD (where D is the diameter of the cylinder) = 2.05 X105. Impact of a number of parameters e.g., the shape of the VG\'s, number of VG pairs (n), spacing between the VG and the cylinder leading edge (L), lateral gap between the trailing edges of a VG pair (g), streamwise gap between two VG pairs (SVG) and the spacing between the two VG\'s in parallel arrangement (ZVG) etc. were investigated on the horseshoe vortex control. The study is conducted using surface oil flow visualization and surface pressure measurements in low speed wind tunnel. It is observed that all the parameters studied have significant control effect, either by reduction in separation region or by lowering the adverse pressure along the symmetric axis upstream of the juncture.

Key Words
horseshoe vortex; low drag vortex generators; streamwise vortex; series arrangement of vortex generators; parallel arrangement of vortex generators

Address
Md.Y. Younis: Department of Mechanical Engineering, Mirpur University of Science and Technology (MUST), Mirpur 10250 (AJK), Pakistan
Hua Zhang: National Key Laboratory of Fluid Mechanics, Beihang University (BUAA), Beijing 100191, China
Bo Hu: Department of Engineering Mechanics, Shijiazhuang Tiedao University, Shijiazhuang 050043, HeBei, China
Emad Uddin and Jawad Aslam: Department of Mechanical Engineering, SMME, National University of Science and Technology (NUST), H-12, Islamabad, 46000, Pakistan

Abstract
Statistical distributions are very useful in describing wind speed characteristics and in predicting wind power potential of a specified region. Although the Weibull distribution is the most popular one in wind energy literature, it does not seem to be able to perfectly fit all the investigated wind speed data in nature. Thus, many studies are still being conducted to find flexible distribution for modelling wind speed data. In this study, we propose a new Odd-Burr Rayleigh distribution for wind speed characterization. The Odd-Burr Rayleigh distribution with two shape parameters is flexible enough to model different shapes of wind speed data and thus it can be an alternative wind speed distribution for the assessment of wind energy potential. Therefore, suitability of the Odd-Burr Rayleigh distribution is investigated on real wind speed data taken from different regions in the South Africa. Numerical results of the conducted analysis confirm that the new Odd-Burr Rayleigh distribution is suitable for modelling most of the considered real wind speed cases and it also can be used for predicting wind power.

Key Words
wind speed; wind power; odd Burr-Rayleigh distribution; Weibull distribution

Address
Ibrahim Arik: Science and Art Faculty, Bilecik Seyh Edebali University, Dep. of Statistics, 11230, Bilecik, Turkey
Yeliz M. Kantar and Ilhan Usta: Faculty of Science, Department of Statistics, Eskisehir Technical University, 26470, Eskisehir, Turkey

Abstract
This paper described the application of Geospatial Analysis in determining mean wind speed, for wind load calculation imposed to electrical transmission tower structural design. The basic wind speed data on available station obtained from Malaysian Meteorology Department is adjusted by considering terrain and ground roughness factor. The correlation between basic wind speed, terrain factor and ground roughness stated in EN-50341-1 is used to obtain the for overhead transmission line elements 50 m above ground. Terrain factor, and ground roughness, in this study are presented by land use types of study area. Wind load is then calculated by using equation stated in design code EN-50341-1 by using the adjusted mean wind speed. Scatter plots of for different and are presented in this paper to see the effect of these parameters to the value of . Geospatial analysis is used to represent the model of . This model can be used to determine possible area that will subject to wind load which severe to the stability of transmission tower and transmission line.

Key Words
geospatial analysis; mean wind speed; wind loading; transmission tower; structural design

Address
Nur H. Hamzah: College of Graduate Studies, Universiti Tenaga Nasional, Kajang, Malaysia
Fathoni Usman: Institute of Energy Infrastructure, Universiti Tenaga Nasional, Kajang, Malaysia

Abstract
In coastal regions, it is common to witness significant damages on low-rise buildings caused by hurricanes and other extreme wind events. These damages start at high pressure zones or weak building components, and then cascade to other building parts. The state-of-the-art in experimental and numerical aerodynamic load evaluation is to assume buildings with intact envelopes where wind acts only on the external walls and correct for internal pressure through separate aerodynamic studies. This approach fails to explain the effect of openings on (i) the external pressure, (ii) internal partition walls; and (iii) the load sharing between internal and external walls. During extreme events, non-structural components (e.g., windows, doors or roof tiles) could fail allowing the wind flow to enter the building, which can subject the internal walls to lateral loads that potentially can exceed their load capacities. Internal walls are typically designed for lower capacities compared to external walls. In the present work, an anticipated damage development scenario is modelled for a four-story building with a stepped gable roof. LES is used to examine the change in the internal and external wind flows for different level of assumed damages (starting from an intact building up to a case with failure in most windows and doors are observed). This study demonstrates that damages in non-structural components can increase the wind risk on the structural elements due to changes in the loading patterns. It also highlights the load sharing mechanisms in low rise buildings.

Key Words
low-rise building; wind load; aerodynamics; load sharing; progressive damage aerodynamics; turbulence, Large Eddy Simulation (LES); Computational Fluid Dynamics (CFD)

Address
Ahmed Elshaer: Department of Civil Engineering, Lakehead University, 955 Oliver Rd, Thunder Bay, ON P7B 5E1, Canada
Girma Bitsuamlak and Hadil Abdallah: Department of Civil & Environmental Engineering, Western University,
1151 Richmond St, London, ON N6A 3K7, Canada



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