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Steave C. Selvaduray

Publications and source records attributed to Steave C. Selvaduray.

3 recordsLinked to original sources

Equation system describing the radiation intensity and the air motion with the water phase transition

In this paper we consider the equation system describing the motion of the air and the variation of the radiation intensity and the quantity of water droplets in the air, including also the process of water phase transition. Under a suitable condition we prove the existence and uniqueness of the local solution. By eliminating the approximation by regularization of vapor density and by including the equation of radiation, this result improves previous ones.

math.AP↗

Global solution for the coagulation equation of water droplets in atmosphere between two horizontal planes

In this paper we give a global existence and uniqueness theorem for an initial and boundary value problem (IBVP) relative to the coagulation equation of water droplets and we show the convergence of the global solution to the stationary solution. The coagulation equation is an integro-differential equation that describes the variation of the density $σ$ of water droplets in the atmosphere. Furthermore, IBVP is considered on a strip limited by two horizontal planes and its boundary condition is such that rain fall from the strip. To obtain this result of global existence of the solution $σ$ in the space of bounded continuous functions, through the method of characteristics, we assume bounded continuous and small data, whereas the vector field, besides being bounded continuous, has $W^{1,\infty}-$ regularity in space.

math.AP↗

An Initial and boundary value problem on a strip for a large class of quasilinear hyperbolic systems arising from an atmospheric model

In this paper well-posedness is proved for an initial and boundary value problem (IBVP) relative to a large class of quasilinear hyperbolic systems, in $p+q$ equations, on a strip, arising from a model of $H_2O$-phase transitions in the atmosphere. To obtain this result, first, we extensively study an IBVP for the generic linear transport equation on $S_{t_1 } = (0,t_1 ) \times G$ with uniformly locally Lipschitz data and associated vector field in $L_{x_d }^{-} (S_{t_1 } \times \mathbb{R}^p )$ (this cone of $L_t^\infty (0,t_1 ;L_{(x,y_{loc} )}^\infty (G \times \mathbb{R}^p ))^d $ is not cointained in $W^{1,\infty }_{\left( {t,x,y_{loc} } \right)} \left( {S_{t_1} \times \mathbb{R}^p} \right)^d$), that involves parametric vector functions in $ L^\infty \left( {0,t_1;W^{1,\infty } \left( G \right)} \right)^p$, by the method of characteristics. We obtain that the solution belongs to $W_{(t,x,y_{loc} )}^{1,\infty } (S_{t_1 } \times \mathbb{R}^p )$ and interesting estimates about it. Afterwards, using fixed point arguments, we establish the local existence, in time, and uniqueness of the solution in $W^{1,\infty } \left( {S_{t^* } } \right)^{p+q}$ for our class of quasilinear hyperbolic systems. Finally, we apply this result to study an IBVP for the hyperbolic part of an atmospheric model on the transition of water in the three states, introduced in \cite{[SF]}, such that rain and ice fall from it.

math.AP↗