On the Entropy Production Due to Explosion in Seawater

Entropy: International and Interdisciplinary Journal of Entropy and Information Studies 01/2005; DOI: 10.3390/e7020134
Source: DOAJ

ABSTRACT Abstract: The change in entropy is calculated due to propagation of blast waves, produced by the explosion of spherical charge in sea water, using the energy hypothesis of Thomas. The release of energy is considered as instantaneous and the gravitation of earth is taken into account, assuming the earth to be a sphere of uniform density. For the sake of simplicity, effect of rotation of the earth is not considered. The explosion is considered at different depths. It has been found that the change in entropy of water decreases at different radial points, as the shock moves away from the point of explosion. Explosion occurred at larger depths, produces a smaller change in entropy of water, then the explosion of same energy, at smaller depths. Directional dependence of entropy production and the motion of the shock are also studied. It has been found that, entropy production is larger in upward motion of the underwater shock. However the shock velocity increases in downward direction.

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    ABSTRACT: In this paper, we study the propagation of a shock wave in water, produced by the expansion of a spherical piston with a finite initial radius. The piston path in the x, t plane is a hyperbola. We have considered the following two cases: (i) the piston accelerates from a zero initial velocity and attains a finite velocity asymptotically as t tends to infinity, and (ii) the piston decelerates, starting from a finite initial velocity. Since an analytic approach to this problem is extremely difficult, we have employed the artificial viscosity method of von Neumann & Richtmyer after examining its applicability in water. For the accelerating piston case, we have studied the effect of different initial radii of the piston, different initial curvatures of the piston path in the x, t plane and the different asymptotic speeds of the piston. The decelerating case exhibits the interesting phenomenon of the formation of a cavity in water when the deceleration of the piston is sufficiently high. We have also studied the motion of the cavity boundary up to 550 cycles.
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    Journal of Mathematical Analysis and Applications 03/1966; 13(3):565-576. · 1.05 Impact Factor


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