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Journal : International Journal of Computing Science and Applied Mathematics-IJCSAM

Mathematical Modeling of Pressure on Cylindrical Ellipse using Side by Site Configuration Chairul Imron; Mahmud Yunus
(IJCSAM) International Journal of Computing Science and Applied Mathematics Vol. 1 No. 1 (2015)
Publisher : LPPM Institut Teknologi Sepuluh Nopember

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Abstract

The application of the concept of fluid is often used to solve problems in the daily life. One of them is the problem of fluid around an elliptical cylinder. This study aims to solve the problems of the fluid around two elliptical cylinder configuration with side-by-side using the Navier-Stokes equations. Navier-Stokes equations–incompressible, viscous and unsteady-are solved using finite difference method staggered grid and SIMPLE (Semi Implicit Method for Pressure-Linked Equation) algorithms. Finite difference method is used to complete the grid arrangement, whereas the SIMPLE algorithm is used to obtain components of velocity and pressure value. Results of this study are the pressure value based on fluid flow profile and a mathematical model which received an elliptical cylinder pressure. Profile of fluid flow is simulated by varying the Reynolds number of 100, 1000, 7000, and 10000 as well as variations in the distance between the cylinder with a ratio of 2 <= S/a <= 6 where L is the distance between the cylinder and a is the minor axis of the cylinder ellipse. Then the pressure is calculated based on the value of the received cylinder pressure components. After obtaining the pressure value, then we create a mathematical model of the stresses imposed on the elliptical cylinder.
Numerical Simulation of Fluid Flow Around Circular Cylinder and Three Passive Controls to Reduce Drag Coefficient at Re=500 Chairul Imron; Amirul Hakam; Basuki Widodo; Tri Yogi Yuwono
(IJCSAM) International Journal of Computing Science and Applied Mathematics Vol. 6 No. 1 (2020)
Publisher : LPPM Institut Teknologi Sepuluh Nopember

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Abstract

Numerical experiments and simulations of fluid flow through the outer surface of a circular cylinder and three passive controls have been investigated to determine the proper configuration of three passive controls in reducing the drag coefficient. One of passive controls is placed in front of the cylinder with distance ratio (S:D) = 2:4 and the other two passive controls are placed behind the cylinder with distance ratio (T:D) = 1:6;1:8. The angle between two passive controls behind the cylinder are a =30 deg;60 deg;90 deg;120 deg. The Navier-Stokes equations for incompressible, viscous and unsteady fluid flows is solved based on SIMPLE (Semi-Implicit for Pressure-Linked Equations) algorithms and discretized using finite-difference method. The difference in a affects the reduction in the drag coefficient significantly. The best configuration of three passive controls design is one of passive controls put at the distance ratio S=D = 2:4;T=D = 1:6 and a = 60. This configuration can reduce the drag coefficient optimally to 21.2109%.
Optimal Control of the Spread of Dengue Fever by Controlling the Vectors Growth Affected by Climate Change and Treatment Basuki Widodo; Nur Asiyah; Aulia Rahma; Kamiran Kamiran; Chairul Imron
(IJCSAM) International Journal of Computing Science and Applied Mathematics Vol. 10 No. 2 (2024)
Publisher : LPPM Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j24775401.ijcsam.v10i2.4586

Abstract

Dengue Hemorrhagic Fever (DHF) is an infectious disease caused by the dengue virus and is spread through the bite of an adult female Aedes aegypti mosquito, as a vector (disease-carrying animal), to humans. This disease is still a major health problem in tropical and subtropical regions. Indonesia is reported as the 2nd highest country among 30 other endemic countries. Warm temperatures during the rainy season are ideal conditions for mosquitoes to lay eggs optimally, increasing egg maturity, and shortening the virus incubation period. This has an impact on increasing the number of mosquitoes and the risk of disease transmission. In this study, control of DHF was carried out by controlling the growth of vectors in the egg and adult phases of mosquitoes, which were influenced by rainfall and air temperature, as well as the treatment of infected humans. Before carrying out the control, stability analysis around the equilibrium point is first conducted. Next, the numerical solution is obtained using the Runge-Kutta method of order 4 with the help of MATLAB software. The results of the analysis show that, based on the optimal control effect in the form of mosquito egg death (k1), adult mosquito death (k2), and human treatment (k3), in the cities of Pekanbaru and Solok, there is not much difference between the two. However, there is a slight difference in the increase in the human population that is susceptible to disease.
Effect of Major Axis Length to the Pressure on Ellips Chairul Imron; Erna Apriliani
(IJCSAM) International Journal of Computing Science and Applied Mathematics Vol. 2 No. 3 (2016)
Publisher : LPPM Institut Teknologi Sepuluh Nopember

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Abstract

Fluid concept has been widely applied to solve problems of daily life, one example is the problem of fluid flow around an elliptical cylinder. We have a goal to solve the problem of fluid flow through three cylindrical ellipses using side-by-side configuration. The equation we use to solve the problem is the Navier-Stokes equations, incompressible, viscous and unsteady. We use the finite difference method with a uniform grid and SIMPLE (Semi Implicit Method for Pressure-Linked Equations) algorithms. Results of this study were used to obtain the amount of pressure that is received by an ellipse in the middle and to construct mathematical models. The profile of the fluid flow is simulated by varying the length of the major axis of the ellipse in the middle where K/5a = 1.0; 1.1; 1.2; 1.3; 1.4 and 1.5 and Reynolds Re = 3.000 and the distance between the ellipse is 3.