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All Journal Journal of the Indonesian Mathematical Society Journal of Science and Applicative Technology
Warsoma Djohan
Unknown Affiliation
Civil Engineering, Building, Construction & Architecture Earth & Planetary Sciences Engineering Materials Science & Nanotechnology Mathematics Mechanical Engineering

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Fourth Order PDE: Model of Thin Film Flow Involving Surface Tension Wiryanto, Leo Hari; Djohan, Warsoma
Journal of the Indonesian Mathematical Society Vol. 31 No. 2 (2025): JUNE
Publisher : IndoMS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22342/jims.v31i2.1454

Abstract

Surface wave on thin film is considered by involving surface tension. The fluid flows on an inclined channel. The model is based on lubrication theory, and presented in a single equation of the thickness of the fluid as wave movement, and the equation is strongly nonlinear. In solving the model, scaling and linearized processes are applied. So that three physical parameters play an important role in the wave propagation: bottom inclination, length of the scaling and the surface tension. Each of those parameters is represented as a term in the equation. Then, the equation is solved numerically by an implicit finite difference method for the linearized equation, so that the solution can be used to observe the effect of those physical quantities. We found that the surface wave propagates with different speed and reducing the amplitude. When the surface tension is involved, the profile of the wave slightly changes, beside it also effect to the movement of the wave. This is simulated in this paper.
OPTIMIZATION OF FUNCTION OF TWO VARIABLES, A NUMERICAL APPROACH Wiryanto, Leo Hari; Djohan, Warsoma
Journal of Science and Applicative Technology Vol. 8 No. 1 (2024): Journal of Science and Applicative Technology June Chapter
Publisher : Lembaga Penelitian dan Pengabdian Masyarakat (LPPM), Institut Teknologi Sumatera, Lampung Selatan, Lampung, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35472/jsat.v8i1.1855

Abstract

Teaching development in maximum value of a function of two variables is reported in this paper. Based on an experience in teaching numerical method, difficulty in determining step size of steepest ascent gives an idea to covert the function into one variable, so that we can solve numerically by standar method for that function, such as Newton method. Here, we present some examples to support that development.
Co-Authors Leo Hari Wiryanto Leo Hari Wiryanto, Leo Hari