Elimination of pinned spiral waves by electrical forcing in excitable chemical media

Name: Porramain Porjai

LCSH: Kasetsart University -- Dissertations. Ph.D. (Physics) 2016

Classification :.LCCS: QC174.24.S65

LCSH: Kasetsart University. Department of Physics -- Theses

LCSH: Spiral waves

LCSH: Nonlinear systems

Abstract: In this work, we present a study on elimination of pinned spiral waves by electrical forcing in excitable chemical media, the Belousov-Zhabotinsky reaction, and numerical simulations with the Oregonator model. The investigation is comprised of two parts: I. Unpinning of spiral waves from small and large circular obstacles, II. Effect of obstacle shapes on pinning and unpinning phenomena. In part I, we present observations on the electrically forced release of spiral waves pinned to unexcitable circular obstacles. When the applied electric current density reaches the necessary current density Junpin, the spiral tip is detached and subsequently drifts away from the obstacle. Junpin is found to increase with the obstacle diameter d. The growth rate ∆Junpin/∆d is much higher for obstacles larger than the free spiral core as compared to that for smaller obstacles. In part II, we present an investigation of spiral waves pinned to circular and rectangular obstacles with different circumferences. For circular objects, the area always increases with the circumference. In contrast, we varied the circumference of rectangles with equal areas by adjusting their width w and height h. For both obstacle forms, the propagating parameters increase with the circumference, regardless of the obstacle area. Despite these common features of the parameters, the forms of pinned spiral waves depend on the obstacle shapes. For unpinning of spiral waves, we applied electrical forcing to release spiral waves. The results showed that for both cases the necessary strength of forcing for unpinning increased with the circumference. This implies that for such unpinning the circumference has a higher impact than the area, at least for circular and rectangular obstacles.

Kasetsart University. Office of the University Library

Address: Bangkok

Email: tdckulib@ku.ac.th

Name: Chaiya Luengviriya

Role: Thesis Advisor

Created: 2016

Modified: 2023-06-12

Issued: 2023-06-12

วิทยานิพนธ์/Thesis

application/pdf

URL: https://kasetsart.idm.oclc.org/login?url=https://www.lib.ku.ac.th/KUthesis/2559/porramain-por-all.pdf

CallNumber: QC174.24.S65.P68

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Physics

Grantor: Kasetsart University

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