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**Wang, Yongqi ; Hutter, Kolumban** (1999):

*Comparison of Two Entropy Principles and Their Applications in Granular Flows with/without Fluid.*

In: Archives of Mechanics, 51 (5), pp. 605-632. Institute of Fundamental Technological Research, Polish Academy of Sciences, ISSN 0373-2029,

[Article]

## Abstract

Two ENTROPY PRINCIPLES that are commonly used are: (i) the Clausius-Duhem inequality with the procedure of exploitation due to Coleman-Noll (CD-CN), and (ii) the entropy principle of Miiller-Liu (ML). CD-CN makes a priori postulates about the entropy flux and entropy supply and assumes external source terms in (most) balance laws. ML postulate the entropy flux to be a general constitutive variable and treat all field equations as constraints for the exploitation of the entropy principle. These and further differences are explained, and results are presented with the use of both principles for (i) a granular solid with a scalar structure equation, and (ii) for a saturated mixture of granular/fluid constituents with scalar structure equations for each constituent. It is shown that the two entropy principles yield different results. It is further indicated which theories are likely to be problematic when the CD-CN approach is used. These theories are then applied to analyses of steady fully-developed gravity flows down an inclined plane.

Item Type: | Article |
---|---|

Erschienen: | 1999 |

Creators: | Wang, Yongqi ; Hutter, Kolumban |

Title: | Comparison of Two Entropy Principles and Their Applications in Granular Flows with/without Fluid |

Language: | English |

Abstract: | Two ENTROPY PRINCIPLES that are commonly used are: (i) the Clausius-Duhem inequality with the procedure of exploitation due to Coleman-Noll (CD-CN), and (ii) the entropy principle of Miiller-Liu (ML). CD-CN makes a priori postulates about the entropy flux and entropy supply and assumes external source terms in (most) balance laws. ML postulate the entropy flux to be a general constitutive variable and treat all field equations as constraints for the exploitation of the entropy principle. These and further differences are explained, and results are presented with the use of both principles for (i) a granular solid with a scalar structure equation, and (ii) for a saturated mixture of granular/fluid constituents with scalar structure equations for each constituent. It is shown that the two entropy principles yield different results. It is further indicated which theories are likely to be problematic when the CD-CN approach is used. These theories are then applied to analyses of steady fully-developed gravity flows down an inclined plane. |

Journal or Publication Title: | Archives of Mechanics |

Journal volume: | 51 |

Number: | 5 |

Publisher: | Institute of Fundamental Technological Research, Polish Academy of Sciences |

Uncontrolled Keywords: | entropy principle; granular flow; solid-fluid mixture; constitutive equations; gravitational flow |

Divisions: | Study Areas 16 Department of Mechanical Engineering 16 Department of Mechanical Engineering > Fluid Dynamics (fdy) Study Areas > Study Area Mechanic |

Date Deposited: | 23 Aug 2011 14:54 |

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