Documents disponibles écrits par cet auteur

Heat flux estimation in a nonlinear inverse heat conduction problem with moving boundary / Hosein Molavi in Journal of heat transfer, Vol. 132 N° 8 (Août 2010) 

Public ISBD [article]  in Journal of heat transfer > Vol. 132 N° 8 (Août 2010) . - pp. [081301-1/10] Titre : Heat flux estimation in a nonlinear inverse heat conduction problem with moving boundary Type de document : texte imprimé Auteurs : Hosein Molavi, Auteur ; Ramin K. Rahmani, Auteur ; Alireza Pourshaghaghy, Auteur Article en page(s) : pp. [081301-1/10] Note générale : Physique Langues : Anglais (eng) Mots-clés : Adjoint  problem  Estimation  of  heat  flux  Gradient-typeods  Inverse  problem  Moving  boundary Index. décimale : 536 Chaleur. Thermodynamique Résumé : The estimation of heat flux in the nonlinear heat conduction problem becomes more challenging when the material at the boundary loses its mass due to phase change, chemical erosion, oxidation, or mechanical removal. In this paper, a new gradient-type method with an adjoint problem is employed to predict the unknown time-varying heat flux at the receding surface in the nonlinear heat conduction problem. Particular features of this novel approach are discussed and examined. Results obtained by the new method for several test cases are benchmarked and analyzed using numerical experiments with simulated exact and noisy measurements. Exceedingly reliable estimation on the heat flux can be obtained from the knowledge of the transient temperature recordings, even in the case with measurement errors. In order to evaluate the performance characteristics of the present inverse scheme, simulations are conducted to analyze the effects of this technique with regard to the conjugate gradient method with an adjoint problem and variable metric method with an adjoint problem. The results obtained show that the present inverse scheme distinguishably accelerates the convergence rate, which approve the well capability of the method for this type of heat conduction problems. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Heat flux estimation in a nonlinear inverse heat conduction problem with moving boundary [texte imprimé] / Hosein Molavi, Auteur ; Ramin K. Rahmani, Auteur ; Alireza Pourshaghaghy, Auteur . - pp. [081301-1/10]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 8 (Août 2010) . - pp. [081301-1/10] Mots-clés : Adjoint  problem  Estimation  of  heat  flux  Gradient-typeods  Inverse  problem  Moving  boundary Index. décimale : 536 Chaleur. Thermodynamique Résumé : The estimation of heat flux in the nonlinear heat conduction problem becomes more challenging when the material at the boundary loses its mass due to phase change, chemical erosion, oxidation, or mechanical removal. In this paper, a new gradient-type method with an adjoint problem is employed to predict the unknown time-varying heat flux at the receding surface in the nonlinear heat conduction problem. Particular features of this novel approach are discussed and examined. Results obtained by the new method for several test cases are benchmarked and analyzed using numerical experiments with simulated exact and noisy measurements. Exceedingly reliable estimation on the heat flux can be obtained from the knowledge of the transient temperature recordings, even in the case with measurement errors. In order to evaluate the performance characteristics of the present inverse scheme, simulations are conducted to analyze the effects of this technique with regard to the conjugate gradient method with an adjoint problem and variable metric method with an adjoint problem. The results obtained show that the present inverse scheme distinguishably accelerates the convergence rate, which approve the well capability of the method for this type of heat conduction problems. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]

A novel methodology for combined parameter and function estimation problems / Hosein Molavi in Journal of heat transfer, Vol. 132 N° 12 (Décembre 2010) 

Public ISBD [article]  in Journal of heat transfer > Vol. 132 N° 12 (Décembre 2010) . - pp. [121301-1/11] Titre : A novel methodology for combined parameter and function estimation problems Type de document : texte imprimé Auteurs : Hosein Molavi, Auteur ; Ali Hakkaki-Fard, Auteur ; Ramin K. Rahmani, Auteur Année de publication : 2010 Article en page(s) : pp. [121301-1/11] Note générale : Physique Langues : Anglais (eng) Mots-clés : Box-Kanemasu  method  Conjugate  gradient  method  Function  estimation  Parameter  estimation Index. décimale : 536 Chaleur. Thermodynamique Résumé : This article presents a novel methodology, which is highly efficient and simple to implement, for simultaneous retrieval of a complete set of thermal coefficients in combined parameter and function estimation problems. Moreover, the effect of correlated unknown variables on convergence performance is examined. The present methodology is a combination of two different classical methods: The conjugate gradient method with adjoint problem (CGMAP) and Box–Kanemasu method (BKM). The methodology uses the benefit of CGMAP in handling function estimation problems and BKM for parameter estimation problems. One of the unique features about the present method is that the correlation among the separate unknowns does not disrupt the convergence of the problem. Numerical experiments using measurement errors are performed to verify the efficiency of the proposed method in solving the combined parameter and function estimation problems. The results obtained by the present approach show that the combined procedure can efficiently and reliably estimate the values of the unknown thermal coefficients. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] A novel methodology for combined parameter and function estimation problems [texte imprimé] / Hosein Molavi, Auteur ; Ali Hakkaki-Fard, Auteur ; Ramin K. Rahmani, Auteur . - 2010 . - pp. [121301-1/11]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 12 (Décembre 2010) . - pp. [121301-1/11] Mots-clés : Box-Kanemasu  method  Conjugate  gradient  method  Function  estimation  Parameter  estimation Index. décimale : 536 Chaleur. Thermodynamique Résumé : This article presents a novel methodology, which is highly efficient and simple to implement, for simultaneous retrieval of a complete set of thermal coefficients in combined parameter and function estimation problems. Moreover, the effect of correlated unknown variables on convergence performance is examined. The present methodology is a combination of two different classical methods: The conjugate gradient method with adjoint problem (CGMAP) and Box–Kanemasu method (BKM). The methodology uses the benefit of CGMAP in handling function estimation problems and BKM for parameter estimation problems. One of the unique features about the present method is that the correlation among the separate unknowns does not disrupt the convergence of the problem. Numerical experiments using measurement errors are performed to verify the efficiency of the proposed method in solving the combined parameter and function estimation problems. The results obtained by the present approach show that the combined procedure can efficiently and reliably estimate the values of the unknown thermal coefficients. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]