Maria Fernanda Natale - Academia.edu (original) (raw)
Papers by Maria Fernanda Natale
arXiv (Cornell University), Feb 25, 2019
In this chapter we consider different approximations for the onedimensional one-phase Stefan prob... more In this chapter we consider different approximations for the onedimensional one-phase Stefan problem corresponding to the fusion process of a semi-infinite material with a temperature boundary condition at the fixed face and non-linear temperature-dependent thermal conductivity. The knowledge of the exact solution of this problem, allows to compare it directly with the approximate solutions obtained by applying the heat balance integral method, an alternative form to it and the refined balance integral method, assuming a quadratic temperature profile in space. In all cases, the analysis is carried out in a dimensionless way by the Stefan number (Ste) parameter.
MAT Serie A, 2004
We study a one-phase Stefan problem for a semi-in¯nite material with temperaturedependent thermal... more We study a one-phase Stefan problem for a semi-in¯nite material with temperaturedependent thermal conductivity with a constant temperature or a heat°ux condition of the type ¡q 0 = p t (q 0 > 0) at the¯xed face x = 0. We obtain in both cases su±cient conditions for data in order to have a parametric representation of the solution of the similarity type for t¸t 0 > 0 with t 0 an arbitrary positive time. These explicit solutions are obtained through the unique solution of an integral equation with the time as a parameter.
International Journal of Heat and Mass Transfer, 1983
Formulas are obtained for the simultaneous determination oftwo of the four coefficients,k (therma... more Formulas are obtained for the simultaneous determination oftwo of the four coefficients,k (thermal conductivity),/ (latent heat of fusion), c (specific heat) , p (mass den sity), of a material occupying a semi-infinite medium. This determination is obtained through an inverse one-phase Lame-Clapeyron (Stefan) problem with an overspecified condition on the fixed face of the phase ch ange material. To so lve this problem, we assume th at the coefficients /'0,CT, 0 0 > 0 are known from experiments (where h o characterizes the heat flux through the fixed face, CT characterizes the mo ving boundary and 0 0 is the temperature on the fixed face). Denoting th e temperature by 0,the results we obtain concerning the associated moving boundary problem are the following : (i) When one of the triples {O,k,/}, {O,k,p} is to be found, the corresponding moving boundary problem always has a solution of the Lame-Clapeyron-Neumann typ e. (ii) If one of the triples {O,k,e}, {O,/,e}, {O,/,p}, and {O,c,p} has to be determined , the above property is satisfied if and only if a complementary condition for the data is verified, Formulas are also obtained for the simult aneous determination of other physical coefficients a nd the inequality~2 < Slej2(Ste :Stefan number) for the coefficient~of the free boundary 5(t) = 2a~t 1/2 of the Lame-Clapeyron solution of the one-phase Stefan problem without unknown coefficients.
A one-phase Stefan problem for a semi-infinite material is studied for special functional forms o... more A one-phase Stefan problem for a semi-infinite material is studied for special functional forms of the thermal conductivity and specific heat depending on the temperature of the phase-change material. Using the similarity transformation technique, an explicit solution for these situations are shown. The mathematical analysis is made for two different kinds of heat source terms, and the existence and uniqueness of the solutions are proved.
Thermal Science, 2018
We consider two different Stefan problems for a semi-infinite material for the non-classical heat... more We consider two different Stefan problems for a semi-infinite material for the non-classical heat equation with a source that depends on the heat flux at the fixed face. One of them, with constant temperature at the fixed face, was already studied in literature and the other, with a convective boundary condition at the fixed face, is presented in this work. Due to the complexity of the exact solution it is of interest to compare with approximate solutions obtained by applying heat balance integral methods, assuming a quadratic temperature profile in space. A dimensionless analysis is carried out by using the parameters: Stefan number and the generalized Biot number. In addition it is studied the case when Biot number goes to infinity, recovering the approximate solutions when a Dirichlet condition is imposed at the fixed face. Some numerical simulations are provided in order to verify the accuracy of the approximate methods.
Electronic Journal of Differential Equations
In this article, we define a p-generalized modified error function as the solution to a non-linea... more In this article, we define a p-generalized modified error function as the solution to a non-linear ordinary differential equation of second order, with a Robin type boundary condition at x=0. We prove existence and uniqueness of a non-negative \(C^{\infty}\) solution by using a fixed point argument. We show that the p-generalized modified error function converges to the p-modified error function defined as the solution to a similar problem with a Dirichlet boundary condition. In both problems, for p=1, the generalized modified error function and the modified error function are recovered. In addition, we analyze the existence and uniqueness of solution to a problem with a Neumann boundary condition. For more information see https://ejde.math.txstate.edu/Volumes/2020/35/abstr.html
International Journal of Non-Linear Mechanics
Differential and Integral Equations
The mathematical analysis of two one-phase unidimensional and non-classical Stefan problems with ... more The mathematical analysis of two one-phase unidimensional and non-classical Stefan problems with nonlinear thermal coecients is obtained. Two related cases are considered, one of them has a temperature condition on the fixed face x = 0 and the other one has a flux condition of the type q0= p t (q0 > 0) : In the first case, the source function depends on the heat flux at the fixed face x = 0; and in the other case it depends on the temperature at the fixed face x = 0: In both cases, we obtain sufficient conditions in order to have the existence of an explicit solution of a similarity type, which is given by using a double fixed point.Fil: Briozzo, Adriana Clotilde. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Austral. Facultad de Cs.empresariales. Departamento de Matemáticas; ArgentinaFil: Natale, María Fernanda. Universidad Austral. Facultad de Cs.empresariales. Departamento de Matemáticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Authorea
We consider a non-linear two-phase unidimensional Stefan problem, which consists on a solidificat... more We consider a non-linear two-phase unidimensional Stefan problem, which consists on a solidification process, for a semi-infinite material x > 0, with phase change temperature T 1 , an initial temperature T 2 > T 1 and a convective boundary condition imposed at the fixed face x = 0 characterized by a heat transfer coefficient h > 0. We assume that the volumetric heat capacity and the thermal conductivity are particular nonlinear functions of the temperature in both solid and liquid phases and they verify a Storm-type relation. A certain inequality on the coefficient h is established in order to get an instantaneous phase change process. We determine sufficient conditions on the parameters of the problem in order to prove the existence and uniqueness of a parametric explicit solution for the Stefan problem.
Mathematical Methods in the Applied Sciences, 2020
We consider a two‐phase Stefan problem for a semi‐infinite body with a convective boundary condit... more We consider a two‐phase Stefan problem for a semi‐infinite body with a convective boundary condition including a density jump at the free boundary with a time‐dependent heat transfer coefficient of the type , whose solution was given in D. A. Tarzia, PAMM. Proc. Appl. Math. Mech. 7, 1040307–1040308 (2007). We demonstrate that the solution to this problem converges to the solution to the analogous one with a temperature boundary condition when the heat transfer coefficient . Moreover, we analyze the dependence of the free boundary respecting to the jump density.
Nonlinear Analysis: Real World Applications, 2020
One dimensional Stefan problems for a semi-infinite material with temperature dependent thermal c... more One dimensional Stefan problems for a semi-infinite material with temperature dependent thermal coefficients are considered. Existence and uniqueness of solution are obtained imposing a Dirichlet or a Robin type condition at fixed face x = 0. Moreover, it is proved that the solution of the problem with the Robin type condition converges to the solution of the problem with the Dirichlet condition at the fixed face. Computational examples are provided.
Nonlinear Analysis: Real World Applications, 2019
A non-classical one dimensional Stefan problem with thermal coefficients temperature dependent an... more A non-classical one dimensional Stefan problem with thermal coefficients temperature dependent and a Robin type condition at fixed face x = 0 for a semi-infinite material is considered. The source function depends on the evolution the heat flux at the fixed face x = 0. Existence of a similarity type solution is obtained and the asymptotic behaviour of free boundary with respect to latent heat fusion is studied. The analysis of several particular cases are given.
MAT Serie A, 2008
We study a one-phase Stefan problem for a semi-infinite material with temperaturedependent therma... more We study a one-phase Stefan problem for a semi-infinite material with temperaturedependent thermal conductivity and a convective term with a constant temperature boundary condition or a heat flux boundary condition of the type −q 0 / √ t (q 0 > 0) at the fixed face x = 0. We obtain in both cases sufficient conditions for data in order to have a parametric representation of the solution of the similarity type for t ≥ t 0 > 0 with t 0 an arbitrary positive time. We improve the results given in
MAT Serie A, 2004
A two-phase Stefan problem with heat source terms in both liquid and solid phases for a semi-in¯n... more A two-phase Stefan problem with heat source terms in both liquid and solid phases for a semi-in¯nite phase-change material is considered. The internal heat source functions are given by g j (x; t) = (¡1) j+1 ½l t exp ³ ¡(x 2a j p t + d j) 2´(j = 1 solid phase; j = 2 liquid phase), ½ is the mass density, l is the fusion latent heat by unit of mass; a 2 j is the di®usion coe±cient, x is spatial variable, t is the temporal variable and d j 2 R. A similarity solution is obtained for any data when a temperature boundary condition is imposed at the¯xed face x = 0; when a°ux condition of the type ¡q 0 = p t (q 0 > 0) is imposed on x = 0 then there exists a similarity solution if and only if a restriction on q 0 is satis¯ed.
Zeitschrift für angewandte Mathematik und Physik, 2017
We study the supercooled one-phase Stefan problem for a semi-infinite material with temperature-d... more We study the supercooled one-phase Stefan problem for a semi-infinite material with temperature-dependent thermal conductivity at the fixed face x = 0. We obtain sufficient conditions for data in order to have existence of a solution of similarity type, local in time and finite-time blow-up occurs. This explicit solution is obtained through the unique solution of an integral equation with the time as a parameter.
Zeitschrift für angewandte Mathematik und Physik, 2016
We consider a nonlinear one-dimensional Stefan problem for a semi-infinite material x > 0, with p... more We consider a nonlinear one-dimensional Stefan problem for a semi-infinite material x > 0, with phase change temperature T f. We assume that the heat capacity and the thermal conductivity satisfy a Storm's condition and we assume a convective boundary condition at the fixed face x = 0. An unique explicit solution of similarity type is obtained. Moreover, asymptotic behavior of the solution when h → +∞ is studied.
Journal of Applied Analysis, 2015
We study a one-phase Stefan problem for a semi-infinite material with temperature-dependent therm... more We study a one-phase Stefan problem for a semi-infinite material with temperature-dependent thermal conductivity with a boundary condition of Robin type at the fixed face x = 0. We obtain sufficient conditions for data in order to have a parametric representation of the solution of similarity type for t ≥ t 0 > 0 with t 0 an arbitrary positive time. This explicit solution is obtained through the unique solution of an integral equation with the time as a parameter.
arXiv (Cornell University), Feb 25, 2019
In this chapter we consider different approximations for the onedimensional one-phase Stefan prob... more In this chapter we consider different approximations for the onedimensional one-phase Stefan problem corresponding to the fusion process of a semi-infinite material with a temperature boundary condition at the fixed face and non-linear temperature-dependent thermal conductivity. The knowledge of the exact solution of this problem, allows to compare it directly with the approximate solutions obtained by applying the heat balance integral method, an alternative form to it and the refined balance integral method, assuming a quadratic temperature profile in space. In all cases, the analysis is carried out in a dimensionless way by the Stefan number (Ste) parameter.
MAT Serie A, 2004
We study a one-phase Stefan problem for a semi-in¯nite material with temperaturedependent thermal... more We study a one-phase Stefan problem for a semi-in¯nite material with temperaturedependent thermal conductivity with a constant temperature or a heat°ux condition of the type ¡q 0 = p t (q 0 > 0) at the¯xed face x = 0. We obtain in both cases su±cient conditions for data in order to have a parametric representation of the solution of the similarity type for t¸t 0 > 0 with t 0 an arbitrary positive time. These explicit solutions are obtained through the unique solution of an integral equation with the time as a parameter.
International Journal of Heat and Mass Transfer, 1983
Formulas are obtained for the simultaneous determination oftwo of the four coefficients,k (therma... more Formulas are obtained for the simultaneous determination oftwo of the four coefficients,k (thermal conductivity),/ (latent heat of fusion), c (specific heat) , p (mass den sity), of a material occupying a semi-infinite medium. This determination is obtained through an inverse one-phase Lame-Clapeyron (Stefan) problem with an overspecified condition on the fixed face of the phase ch ange material. To so lve this problem, we assume th at the coefficients /'0,CT, 0 0 > 0 are known from experiments (where h o characterizes the heat flux through the fixed face, CT characterizes the mo ving boundary and 0 0 is the temperature on the fixed face). Denoting th e temperature by 0,the results we obtain concerning the associated moving boundary problem are the following : (i) When one of the triples {O,k,/}, {O,k,p} is to be found, the corresponding moving boundary problem always has a solution of the Lame-Clapeyron-Neumann typ e. (ii) If one of the triples {O,k,e}, {O,/,e}, {O,/,p}, and {O,c,p} has to be determined , the above property is satisfied if and only if a complementary condition for the data is verified, Formulas are also obtained for the simult aneous determination of other physical coefficients a nd the inequality~2 < Slej2(Ste :Stefan number) for the coefficient~of the free boundary 5(t) = 2a~t 1/2 of the Lame-Clapeyron solution of the one-phase Stefan problem without unknown coefficients.
A one-phase Stefan problem for a semi-infinite material is studied for special functional forms o... more A one-phase Stefan problem for a semi-infinite material is studied for special functional forms of the thermal conductivity and specific heat depending on the temperature of the phase-change material. Using the similarity transformation technique, an explicit solution for these situations are shown. The mathematical analysis is made for two different kinds of heat source terms, and the existence and uniqueness of the solutions are proved.
Thermal Science, 2018
We consider two different Stefan problems for a semi-infinite material for the non-classical heat... more We consider two different Stefan problems for a semi-infinite material for the non-classical heat equation with a source that depends on the heat flux at the fixed face. One of them, with constant temperature at the fixed face, was already studied in literature and the other, with a convective boundary condition at the fixed face, is presented in this work. Due to the complexity of the exact solution it is of interest to compare with approximate solutions obtained by applying heat balance integral methods, assuming a quadratic temperature profile in space. A dimensionless analysis is carried out by using the parameters: Stefan number and the generalized Biot number. In addition it is studied the case when Biot number goes to infinity, recovering the approximate solutions when a Dirichlet condition is imposed at the fixed face. Some numerical simulations are provided in order to verify the accuracy of the approximate methods.
Electronic Journal of Differential Equations
In this article, we define a p-generalized modified error function as the solution to a non-linea... more In this article, we define a p-generalized modified error function as the solution to a non-linear ordinary differential equation of second order, with a Robin type boundary condition at x=0. We prove existence and uniqueness of a non-negative \(C^{\infty}\) solution by using a fixed point argument. We show that the p-generalized modified error function converges to the p-modified error function defined as the solution to a similar problem with a Dirichlet boundary condition. In both problems, for p=1, the generalized modified error function and the modified error function are recovered. In addition, we analyze the existence and uniqueness of solution to a problem with a Neumann boundary condition. For more information see https://ejde.math.txstate.edu/Volumes/2020/35/abstr.html
International Journal of Non-Linear Mechanics
Differential and Integral Equations
The mathematical analysis of two one-phase unidimensional and non-classical Stefan problems with ... more The mathematical analysis of two one-phase unidimensional and non-classical Stefan problems with nonlinear thermal coecients is obtained. Two related cases are considered, one of them has a temperature condition on the fixed face x = 0 and the other one has a flux condition of the type q0= p t (q0 > 0) : In the first case, the source function depends on the heat flux at the fixed face x = 0; and in the other case it depends on the temperature at the fixed face x = 0: In both cases, we obtain sufficient conditions in order to have the existence of an explicit solution of a similarity type, which is given by using a double fixed point.Fil: Briozzo, Adriana Clotilde. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Austral. Facultad de Cs.empresariales. Departamento de Matemáticas; ArgentinaFil: Natale, María Fernanda. Universidad Austral. Facultad de Cs.empresariales. Departamento de Matemáticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Authorea
We consider a non-linear two-phase unidimensional Stefan problem, which consists on a solidificat... more We consider a non-linear two-phase unidimensional Stefan problem, which consists on a solidification process, for a semi-infinite material x > 0, with phase change temperature T 1 , an initial temperature T 2 > T 1 and a convective boundary condition imposed at the fixed face x = 0 characterized by a heat transfer coefficient h > 0. We assume that the volumetric heat capacity and the thermal conductivity are particular nonlinear functions of the temperature in both solid and liquid phases and they verify a Storm-type relation. A certain inequality on the coefficient h is established in order to get an instantaneous phase change process. We determine sufficient conditions on the parameters of the problem in order to prove the existence and uniqueness of a parametric explicit solution for the Stefan problem.
Mathematical Methods in the Applied Sciences, 2020
We consider a two‐phase Stefan problem for a semi‐infinite body with a convective boundary condit... more We consider a two‐phase Stefan problem for a semi‐infinite body with a convective boundary condition including a density jump at the free boundary with a time‐dependent heat transfer coefficient of the type , whose solution was given in D. A. Tarzia, PAMM. Proc. Appl. Math. Mech. 7, 1040307–1040308 (2007). We demonstrate that the solution to this problem converges to the solution to the analogous one with a temperature boundary condition when the heat transfer coefficient . Moreover, we analyze the dependence of the free boundary respecting to the jump density.
Nonlinear Analysis: Real World Applications, 2020
One dimensional Stefan problems for a semi-infinite material with temperature dependent thermal c... more One dimensional Stefan problems for a semi-infinite material with temperature dependent thermal coefficients are considered. Existence and uniqueness of solution are obtained imposing a Dirichlet or a Robin type condition at fixed face x = 0. Moreover, it is proved that the solution of the problem with the Robin type condition converges to the solution of the problem with the Dirichlet condition at the fixed face. Computational examples are provided.
Nonlinear Analysis: Real World Applications, 2019
A non-classical one dimensional Stefan problem with thermal coefficients temperature dependent an... more A non-classical one dimensional Stefan problem with thermal coefficients temperature dependent and a Robin type condition at fixed face x = 0 for a semi-infinite material is considered. The source function depends on the evolution the heat flux at the fixed face x = 0. Existence of a similarity type solution is obtained and the asymptotic behaviour of free boundary with respect to latent heat fusion is studied. The analysis of several particular cases are given.
MAT Serie A, 2008
We study a one-phase Stefan problem for a semi-infinite material with temperaturedependent therma... more We study a one-phase Stefan problem for a semi-infinite material with temperaturedependent thermal conductivity and a convective term with a constant temperature boundary condition or a heat flux boundary condition of the type −q 0 / √ t (q 0 > 0) at the fixed face x = 0. We obtain in both cases sufficient conditions for data in order to have a parametric representation of the solution of the similarity type for t ≥ t 0 > 0 with t 0 an arbitrary positive time. We improve the results given in
MAT Serie A, 2004
A two-phase Stefan problem with heat source terms in both liquid and solid phases for a semi-in¯n... more A two-phase Stefan problem with heat source terms in both liquid and solid phases for a semi-in¯nite phase-change material is considered. The internal heat source functions are given by g j (x; t) = (¡1) j+1 ½l t exp ³ ¡(x 2a j p t + d j) 2´(j = 1 solid phase; j = 2 liquid phase), ½ is the mass density, l is the fusion latent heat by unit of mass; a 2 j is the di®usion coe±cient, x is spatial variable, t is the temporal variable and d j 2 R. A similarity solution is obtained for any data when a temperature boundary condition is imposed at the¯xed face x = 0; when a°ux condition of the type ¡q 0 = p t (q 0 > 0) is imposed on x = 0 then there exists a similarity solution if and only if a restriction on q 0 is satis¯ed.
Zeitschrift für angewandte Mathematik und Physik, 2017
We study the supercooled one-phase Stefan problem for a semi-infinite material with temperature-d... more We study the supercooled one-phase Stefan problem for a semi-infinite material with temperature-dependent thermal conductivity at the fixed face x = 0. We obtain sufficient conditions for data in order to have existence of a solution of similarity type, local in time and finite-time blow-up occurs. This explicit solution is obtained through the unique solution of an integral equation with the time as a parameter.
Zeitschrift für angewandte Mathematik und Physik, 2016
We consider a nonlinear one-dimensional Stefan problem for a semi-infinite material x > 0, with p... more We consider a nonlinear one-dimensional Stefan problem for a semi-infinite material x > 0, with phase change temperature T f. We assume that the heat capacity and the thermal conductivity satisfy a Storm's condition and we assume a convective boundary condition at the fixed face x = 0. An unique explicit solution of similarity type is obtained. Moreover, asymptotic behavior of the solution when h → +∞ is studied.
Journal of Applied Analysis, 2015
We study a one-phase Stefan problem for a semi-infinite material with temperature-dependent therm... more We study a one-phase Stefan problem for a semi-infinite material with temperature-dependent thermal conductivity with a boundary condition of Robin type at the fixed face x = 0. We obtain sufficient conditions for data in order to have a parametric representation of the solution of similarity type for t ≥ t 0 > 0 with t 0 an arbitrary positive time. This explicit solution is obtained through the unique solution of an integral equation with the time as a parameter.