Fluid viscosity is a main feature of fluids; an inviscid fluid does not exist even though a large number of theories has been advanced for flows of such fluids. The velocity of fluid flow may considerably be reduced due to the presence of fluid viscosity both for laminar and turbulent flows. The letters exchanged between de Saint-Venant (dSV) and Boussinesq mainly refer to laminar flow. The most peculiar statement of dSV is that, if the flow in a typical lowland river would be laminar, its velocity would be larger than the speed of sound. It is evident that this statement is wrong because laminar flow has stringent limitations typically expressed by the Reynolds number. The hydraulic resistance is another peculiar feature in hydrodynamics, given that several theories have been advanced which do not at all reflect the everyday experience. One of these is the d’Alembert paradox, stating that the resistance is equal to zero for a steady flow of an inviscid and incompressible fluid. Typically, a body suspended in a large pipe is considered. Applying the momentum equation in the axial direction sufficiently upand downstream of the body, the resistance would indeed become zero, as occurs for potential flows. Again, this is far away from everybody’s experience, such as for a swimmer or a walker under heavy
{"title":"Correspondence between de Saint-Venant and Boussinesq 5: Viscosity and hydraulic resistance","authors":"W. Hager, K. Hutter, O. Castro-Orgaz","doi":"10.5802/CRMECA.71","DOIUrl":"https://doi.org/10.5802/CRMECA.71","url":null,"abstract":"Fluid viscosity is a main feature of fluids; an inviscid fluid does not exist even though a large number of theories has been advanced for flows of such fluids. The velocity of fluid flow may considerably be reduced due to the presence of fluid viscosity both for laminar and turbulent flows. The letters exchanged between de Saint-Venant (dSV) and Boussinesq mainly refer to laminar flow. The most peculiar statement of dSV is that, if the flow in a typical lowland river would be laminar, its velocity would be larger than the speed of sound. It is evident that this statement is wrong because laminar flow has stringent limitations typically expressed by the Reynolds number. The hydraulic resistance is another peculiar feature in hydrodynamics, given that several theories have been advanced which do not at all reflect the everyday experience. One of these is the d’Alembert paradox, stating that the resistance is equal to zero for a steady flow of an inviscid and incompressible fluid. Typically, a body suspended in a large pipe is considered. Applying the momentum equation in the axial direction sufficiently upand downstream of the body, the resistance would indeed become zero, as occurs for potential flows. Again, this is far away from everybody’s experience, such as for a swimmer or a walker under heavy","PeriodicalId":50997,"journal":{"name":"Comptes Rendus Mecanique","volume":"2 1","pages":"145-166"},"PeriodicalIF":0.8,"publicationDate":"2021-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87683992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Hafizh, A. Muthalif, J. Renno, M. R. Paurobally, M. Arab, I. Bahadur, H. Ouakad
Energy harvesting mechanisms can be used to extract energy from ambient surroundings to power small electronic devices, which has a significant advantage in realizing self-sustaining wireless devices. The proposed design of this study uses the internal fluid flow within a pipe and takes advantage of the fluid– structure interaction through flow-induced vibration of a bluff body. The hybrid harvester uses the vibration to convert electrical energy through a piezoelectric material and an electromagnetic oscillator that can be tuned to resonate at the oscillation frequency. A numerical solver was used to estimate harvestable voltage for this submerged hybrid energy harvester model by using ordinary differential equations. A computational study was used to optimize the performance of the bluffbodies under the influence of the vortices for circular, triangular, ellipse, and quadrilateral shapes. Wake development was seen in the circular and triangular shapes with the ellipse having the lowest turbulence kinetic energy among the shapes. Structural deflection of the beam under resonance was compared for the different shapes, which displayed better results for triangular and elliptical bluff bodies.
{"title":"A hybrid piezoelectric–electromagnetic nonlinear vibration energy harvester excited by fluid flow","authors":"M. Hafizh, A. Muthalif, J. Renno, M. R. Paurobally, M. Arab, I. Bahadur, H. Ouakad","doi":"10.5802/CRMECA.74","DOIUrl":"https://doi.org/10.5802/CRMECA.74","url":null,"abstract":"Energy harvesting mechanisms can be used to extract energy from ambient surroundings to power small electronic devices, which has a significant advantage in realizing self-sustaining wireless devices. The proposed design of this study uses the internal fluid flow within a pipe and takes advantage of the fluid– structure interaction through flow-induced vibration of a bluff body. The hybrid harvester uses the vibration to convert electrical energy through a piezoelectric material and an electromagnetic oscillator that can be tuned to resonate at the oscillation frequency. A numerical solver was used to estimate harvestable voltage for this submerged hybrid energy harvester model by using ordinary differential equations. A computational study was used to optimize the performance of the bluffbodies under the influence of the vortices for circular, triangular, ellipse, and quadrilateral shapes. Wake development was seen in the circular and triangular shapes with the ellipse having the lowest turbulence kinetic energy among the shapes. Structural deflection of the beam under resonance was compared for the different shapes, which displayed better results for triangular and elliptical bluff bodies.","PeriodicalId":50997,"journal":{"name":"Comptes Rendus Mecanique","volume":"181 1","pages":"65-81"},"PeriodicalIF":0.8,"publicationDate":"2021-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85560492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The interaction of a viscous fluid and a circular, pre-stressed active shell is studied in the limit of low Reynolds numbers. A seminal paper of Taylor represents a benchmark for this class of problems. Here, inspired by the same approach, we determine with asymptotic techniques the possible swimming motions of the shell for the particular changes of curvature that it can achieve when actuated. We confirm numerical results obtained previously, and highlight the structure of a problem that turns out to be similar to that of Taylor, and as such represents a simple example of Stokesian swimming.
{"title":"Asymptotic approach to a rotational Taylor swimming sheet","authors":"G. Corsi","doi":"10.5802/CRMECA.75","DOIUrl":"https://doi.org/10.5802/CRMECA.75","url":null,"abstract":"The interaction of a viscous fluid and a circular, pre-stressed active shell is studied in the limit of low Reynolds numbers. A seminal paper of Taylor represents a benchmark for this class of problems. Here, inspired by the same approach, we determine with asymptotic techniques the possible swimming motions of the shell for the particular changes of curvature that it can achieve when actuated. We confirm numerical results obtained previously, and highlight the structure of a problem that turns out to be similar to that of Taylor, and as such represents a simple example of Stokesian swimming.","PeriodicalId":50997,"journal":{"name":"Comptes Rendus Mecanique","volume":"8 1","pages":"103-116"},"PeriodicalIF":0.8,"publicationDate":"2021-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74877504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, a new modelling is proposed to describe the viscoplastic behaviour of face-centred cubic (FCC) metals. Creep tests under various conditions were performed. The material chosen to test the model is Al-1050. The plastic deformation is controlled by intragranular diffusion when the test temperature exceeds 0.4Tm . The developed model involves two state variables related to the microstructure: dislocation density and subgrain size. The grain size is assumed to be constant in the intermediate temperature range. Validation tests were proposed to justify the reliability of the developed model in various loading conditions.
{"title":"A contribution to the modelling of creep behaviour of FCC metals","authors":"A. Maati, E. Ouakdi, L. Tabourot, P. Balland","doi":"10.5802/CRMECA.76","DOIUrl":"https://doi.org/10.5802/CRMECA.76","url":null,"abstract":"In this paper, a new modelling is proposed to describe the viscoplastic behaviour of face-centred cubic (FCC) metals. Creep tests under various conditions were performed. The material chosen to test the model is Al-1050. The plastic deformation is controlled by intragranular diffusion when the test temperature exceeds 0.4Tm . The developed model involves two state variables related to the microstructure: dislocation density and subgrain size. The grain size is assumed to be constant in the intermediate temperature range. Validation tests were proposed to justify the reliability of the developed model in various loading conditions.","PeriodicalId":50997,"journal":{"name":"Comptes Rendus Mecanique","volume":"123 1","pages":"55-64"},"PeriodicalIF":0.8,"publicationDate":"2021-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73756594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
David V. Brou, A. B. N’Dri, A. Brou, Aya Brigitte N’Drib, A. B. N’Dri
Thirty-one bush fire experiments are used to assess the predictive capability of a bush fire spread model. This model has been optimized by a deterministic method of parameter calibration. The experiments used were carried out each year from 2014 to 2017 in a forest–savannah transition zone. The characteristics of the herbaceous stratum as well as the meteorological and topographical data are well documented. The characteristics of the fire have also been measured to understand the behaviour of the fire in a Guinean savannah. The predicted rate of fire spread and fire contours gave results in good accordance with those of the experiments. Résumé. Trente et une (31) expériences de feu de brousse ont été utilisées pour évaluer la capacité prédictive d’un modèle de propagation de feux de brousse. Ce modèle a été optimisé par une méthode déterministe de calibrage des paramètres. Les expériences utilisées ont été réalisées chaque année de 2014 à 2017 dans une zone de transition forêt savane. Les caractéristiques de la strate herbacée ainsi que les données météorologiques et topographiques ont été bien documentées. Les caractéristiques du feu ont été également mesurées pour comprendre le comportement du feu dans une savane Guinéenne. Les vitesses de propagation et les contours de feux prédits ont donné des résultats en bon accord avec ceux des expériences.
通过31次丛林火灾试验，对该模型的预测能力进行了评价。采用确定性参数定标法对模型进行了优化。所使用的实验从2014年到2017年每年在森林-草原过渡区进行。草本层的特征以及气象和地形资料都有很好的记录。还测量了火灾的特征，以了解几内亚大草原火灾的行为。预测的火灾蔓延速度和火灾轮廓线与实验结果吻合较好。的简历。Trente et une(31)的实验表明，在交换交换条件下，交换交换条件下，交换交换条件下，交换交换条件下，交换交换条件下，交换交换条件下的交换交换条件。modere a sametest - optimisis = une sametthode dsametiste de calibrage des parpartres。经验，利用，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金，薪金莱斯的特性de la strate herbacee依照ainsi变量的数据meteorologiques et topographiques高频好documentees。“caracacacimristiques du feu”和“acacacimacement measures”和“acacacimacement measures”都可以理解为“acacacimacrestiques du feu”和“savane guinacemoenne”。传播的过程、传播的过程、传播的过程、传播的过程、传播的过程、传播的过程、传播的过程、传播的过程、传播的过程、传播的过程、传播的过程。
{"title":"Evaluation of an optimized bush fire propagation model with large-scale fire experiments","authors":"David V. Brou, A. B. N’Dri, A. Brou, Aya Brigitte N’Drib, A. B. N’Dri","doi":"10.5802/CRMECA.77","DOIUrl":"https://doi.org/10.5802/CRMECA.77","url":null,"abstract":"Thirty-one bush fire experiments are used to assess the predictive capability of a bush fire spread model. This model has been optimized by a deterministic method of parameter calibration. The experiments used were carried out each year from 2014 to 2017 in a forest–savannah transition zone. The characteristics of the herbaceous stratum as well as the meteorological and topographical data are well documented. The characteristics of the fire have also been measured to understand the behaviour of the fire in a Guinean savannah. The predicted rate of fire spread and fire contours gave results in good accordance with those of the experiments. Résumé. Trente et une (31) expériences de feu de brousse ont été utilisées pour évaluer la capacité prédictive d’un modèle de propagation de feux de brousse. Ce modèle a été optimisé par une méthode déterministe de calibrage des paramètres. Les expériences utilisées ont été réalisées chaque année de 2014 à 2017 dans une zone de transition forêt savane. Les caractéristiques de la strate herbacée ainsi que les données météorologiques et topographiques ont été bien documentées. Les caractéristiques du feu ont été également mesurées pour comprendre le comportement du feu dans une savane Guinéenne. Les vitesses de propagation et les contours de feux prédits ont donné des résultats en bon accord avec ceux des expériences.","PeriodicalId":50997,"journal":{"name":"Comptes Rendus Mecanique","volume":"52 1","pages":"43-53"},"PeriodicalIF":0.8,"publicationDate":"2021-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73619080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Based on discrete element method (DEM), three kinds of soil–rock mixture (SRM) models with different coarse particle contents were established and triaxial compression tests were carried out. The results show that the force chains in the particle system playing the main bearing role need more lateral supports, which results in the contact with a higher coordination number and often bear larger contact force. The relationship between the contact’s carrying capacity and the coordination number can be fit by a quadric surface. Taking the fit quadric surface as the capacity function, the network-flow model of force transfer can be constructed to quantify the force transfer ability of a contact network. By connecting the maximum flow in the network with the hardening parameter of the unified hardening model, the stress–strain relationship of SRM can be predicted to some extent, which lays a basis for formulating micro–macro constitutive model for granular materials.
{"title":"Analysis on mechanical properties and evolution of mesostructure of soil–rock mixture samples from contact network perspective","authors":"Ran Xu, E. Liu, H. Xing","doi":"10.5802/CRMECA.73","DOIUrl":"https://doi.org/10.5802/CRMECA.73","url":null,"abstract":"Based on discrete element method (DEM), three kinds of soil–rock mixture (SRM) models with different coarse particle contents were established and triaxial compression tests were carried out. The results show that the force chains in the particle system playing the main bearing role need more lateral supports, which results in the contact with a higher coordination number and often bear larger contact force. The relationship between the contact’s carrying capacity and the coordination number can be fit by a quadric surface. Taking the fit quadric surface as the capacity function, the network-flow model of force transfer can be constructed to quantify the force transfer ability of a contact network. By connecting the maximum flow in the network with the hardening parameter of the unified hardening model, the stress–strain relationship of SRM can be predicted to some extent, which lays a basis for formulating micro–macro constitutive model for granular materials.","PeriodicalId":50997,"journal":{"name":"Comptes Rendus Mecanique","volume":"108 1","pages":"83-102"},"PeriodicalIF":0.8,"publicationDate":"2021-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76424586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We introduce the three-dimensional Eringen system of equations for the nematodynamics of liquid crystals, announce the short time existence and uniqueness of strong solutions for the one-dimensional problem in the periodic case, and show the continuous dependence of the solution on the initial data. Résumé. Nous présentons le système tridimensionnel d’équations d’Eringen pour la nématodynamique des cristaux liquides, annonçons l’existence en temps et l’unicité de solutions fortes pour le problème unidimensionnel dans le cas périodique et montrons la dépendance continue de la solution sur les données initiales.
{"title":"On the Eringen model for nematic liquid crystals","authors":"G. Chechkin, T. Ratiu, M. Romanov","doi":"10.5802/CRMECA.67","DOIUrl":"https://doi.org/10.5802/CRMECA.67","url":null,"abstract":"We introduce the three-dimensional Eringen system of equations for the nematodynamics of liquid crystals, announce the short time existence and uniqueness of strong solutions for the one-dimensional problem in the periodic case, and show the continuous dependence of the solution on the initial data. Résumé. Nous présentons le système tridimensionnel d’équations d’Eringen pour la nématodynamique des cristaux liquides, annonçons l’existence en temps et l’unicité de solutions fortes pour le problème unidimensionnel dans le cas périodique et montrons la dépendance continue de la solution sur les données initiales.","PeriodicalId":50997,"journal":{"name":"Comptes Rendus Mecanique","volume":"15 1","pages":"21-27"},"PeriodicalIF":0.8,"publicationDate":"2021-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79053256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One hundred and fifty years ago, Henri-Édouard Tresca submitted a series of Memoirs to the French Academy of Sciences, which were devoted to recording the extensive series of experiments he had carried out. In these experiments, he had investigated punching, rolling, forging, stamping and extruding processes of various materials, and he had definitely identified a phenomenon that he called the “fluidity” of solids subjected to very high pressures. In addition to the precise description of his experiments, he proposed a mechanical theory for the observed phenomenon. In this theory, the concepts now called yield criterion and plastic flow rule were introduced for the first time.
{"title":"About Tresca’s Memoirs on the fluidity of solids (1864–1870)","authors":"J. Salençon","doi":"10.5802/CRMECA.69","DOIUrl":"https://doi.org/10.5802/CRMECA.69","url":null,"abstract":"One hundred and fifty years ago, Henri-Édouard Tresca submitted a series of Memoirs to the French Academy of Sciences, which were devoted to recording the extensive series of experiments he had carried out. In these experiments, he had investigated punching, rolling, forging, stamping and extruding processes of various materials, and he had definitely identified a phenomenon that he called the “fluidity” of solids subjected to very high pressures. In addition to the precise description of his experiments, he proposed a mechanical theory for the observed phenomenon. In this theory, the concepts now called yield criterion and plastic flow rule were introduced for the first time.","PeriodicalId":50997,"journal":{"name":"Comptes Rendus Mecanique","volume":"25 1","pages":"1-7"},"PeriodicalIF":0.8,"publicationDate":"2021-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76430077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Weakly nonlinear composite conductors are characterized by position-dependent dissipation potentials expressible as an additive composition of a quadratic potential and a nonquadratic potential weighted by a small parameter. This additive form carries over to the effective dissipation potential of the composite when expanded to first order in the small parameter. However, the first-order correction of this asymptotic expansion depends only on the zeroth-order values of the local fields, namely, the local fields within the perfectly linear composite conductor. This asymptotic expansion is exploited to derive the exact effective conductivity of a composite cylinder assemblage exhibiting weak nonlinearity of the power-law type (i.e., power law with exponent m = 1+δ, such that |δ| ¿ 1), and found to be identical (to first order in δ) to the corresponding asymptotic result for sequentially laminated composites of infinite rank. These exact results are used to assess the capabilities of more general nonlinear homogenization methods making use of the properties of optimally selected linear comparison composites.
{"title":"Exact results for weakly nonlinear composites and implications for homogenization methods","authors":"J. Furer, M. I. Idiart, Pedro Ponte Castañeda","doi":"10.5802/CRMECA.66","DOIUrl":"https://doi.org/10.5802/CRMECA.66","url":null,"abstract":"Weakly nonlinear composite conductors are characterized by position-dependent dissipation potentials expressible as an additive composition of a quadratic potential and a nonquadratic potential weighted by a small parameter. This additive form carries over to the effective dissipation potential of the composite when expanded to first order in the small parameter. However, the first-order correction of this asymptotic expansion depends only on the zeroth-order values of the local fields, namely, the local fields within the perfectly linear composite conductor. This asymptotic expansion is exploited to derive the exact effective conductivity of a composite cylinder assemblage exhibiting weak nonlinearity of the power-law type (i.e., power law with exponent m = 1+δ, such that |δ| ¿ 1), and found to be identical (to first order in δ) to the corresponding asymptotic result for sequentially laminated composites of infinite rank. These exact results are used to assess the capabilities of more general nonlinear homogenization methods making use of the properties of optimally selected linear comparison composites.","PeriodicalId":50997,"journal":{"name":"Comptes Rendus Mecanique","volume":"127 1","pages":"893-909"},"PeriodicalIF":0.8,"publicationDate":"2021-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79547505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To fight against forest fires, simple and improved models are more searched out due to the fact they are more easily understandable by the users. This actual model is part of the fire propagation models within a network. It is simple and easy to implement. However, it depends on several parameters that are difficult to measure or estimate precisely beforehand. The prediction by this model is therefore insufficient. A deterministic optimization method is introduced to calibrate its parameters. The optimized model was tested on several laboratory experiments and on two large-scale experimental fires. The comparison of the model results with those of the experiment shows a very significant improvement in its prediction with the optimal parameters. Résumé. Dans la lutte contre les feux de forêt, les modèles simples et améliorés sont plus recherchés car plus aisément compréhensibles par les utilisateurs. Le présent modèle fait partie des modèles de propagation de feu à l’intérieur d’un réseau. Il est simple et facile à mettre en œuvre. Cependant, il dépend de plusieurs paramètres difficiles à mesurer ou à estimer avec précision au préalable. La prédiction par ce modèle est de ce fait insuffisante. Par conséquent, une méthode déterministe d’optimisation est introduite pour calibrer ses paramètres. Le modèle optimisé a été testé sur plusieurs feux de laboratoires et sur deux feux expérimentaux à grande échelle. La comparaison des résultats du modèle avec ceux de l’expérience montre une amélioration très significative de sa prédiction avec les paramètres optimaux.
{"title":"Deterministic optimization techniques to calibrate parameters in a wildland fire propagation model","authors":"M. H. Tchiekre, A. Brou, J. Adou","doi":"10.5802/crmeca.58","DOIUrl":"https://doi.org/10.5802/crmeca.58","url":null,"abstract":"To fight against forest fires, simple and improved models are more searched out due to the fact they are more easily understandable by the users. This actual model is part of the fire propagation models within a network. It is simple and easy to implement. However, it depends on several parameters that are difficult to measure or estimate precisely beforehand. The prediction by this model is therefore insufficient. A deterministic optimization method is introduced to calibrate its parameters. The optimized model was tested on several laboratory experiments and on two large-scale experimental fires. The comparison of the model results with those of the experiment shows a very significant improvement in its prediction with the optimal parameters. Résumé. Dans la lutte contre les feux de forêt, les modèles simples et améliorés sont plus recherchés car plus aisément compréhensibles par les utilisateurs. Le présent modèle fait partie des modèles de propagation de feu à l’intérieur d’un réseau. Il est simple et facile à mettre en œuvre. Cependant, il dépend de plusieurs paramètres difficiles à mesurer ou à estimer avec précision au préalable. La prédiction par ce modèle est de ce fait insuffisante. Par conséquent, une méthode déterministe d’optimisation est introduite pour calibrer ses paramètres. Le modèle optimisé a été testé sur plusieurs feux de laboratoires et sur deux feux expérimentaux à grande échelle. La comparaison des résultats du modèle avec ceux de l’expérience montre une amélioration très significative de sa prédiction avec les paramètres optimaux.","PeriodicalId":50997,"journal":{"name":"Comptes Rendus Mecanique","volume":"175 1","pages":"759-768"},"PeriodicalIF":0.8,"publicationDate":"2020-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85433362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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