The second law of thermodynamics has never been taken into account in the traditional hydrodynamics and numer- ical weather prediction models,which is a serious oversight in the history of mechanics.Introducing the th...The second law of thermodynamics has never been taken into account in the traditional hydrodynamics and numer- ical weather prediction models,which is a serious oversight in the history of mechanics.Introducing the thermodynamic irreversibility into the hydrodynamic systems,the theory and method proposed in this study would not only lead the outputs of a numerical weather prediction model to noticeable improvement,but lead the structure of hydrodynamics to deepgoing transformation.展开更多
In this study, we investigate the entropies of photons, ideal gas-like dust(baryonic matter), and a special kind of dark energy in the context of cosmology. When these components expand freely with the universe, we ca...In this study, we investigate the entropies of photons, ideal gas-like dust(baryonic matter), and a special kind of dark energy in the context of cosmology. When these components expand freely with the universe, we calculate the entropy and specific entropy of each component from the perspective of statistics. Under specific assumptions and conditions, the entropies of these components can satisfy the second law of thermodynamics independently. Our calculations show that the specific entropy of matter cannot be a constant during the expansion of the universe, except for photons. When these components interact with the space-time background, particle production(annihilation) can occur. We study the influence of the interaction on the entropies of these components and obtain the conditions guaranteeing that the entropy of each component satisfies the second law of thermodynamics.展开更多
基金This work is supported by the National Natural Science Foundation of China(Grant No.49275245).
文摘The second law of thermodynamics has never been taken into account in the traditional hydrodynamics and numer- ical weather prediction models,which is a serious oversight in the history of mechanics.Introducing the thermodynamic irreversibility into the hydrodynamic systems,the theory and method proposed in this study would not only lead the outputs of a numerical weather prediction model to noticeable improvement,but lead the structure of hydrodynamics to deepgoing transformation.
基金Supported by the National Natural Science Foundation of China (11875151,12047501,11873001,12047564)Lanzhou City’s scientific research funding subsidy to Lanzhou Universitythe Postdoctoral Science Foundation of Chongqing (cstc2021jcyj-bsh0124)
文摘In this study, we investigate the entropies of photons, ideal gas-like dust(baryonic matter), and a special kind of dark energy in the context of cosmology. When these components expand freely with the universe, we calculate the entropy and specific entropy of each component from the perspective of statistics. Under specific assumptions and conditions, the entropies of these components can satisfy the second law of thermodynamics independently. Our calculations show that the specific entropy of matter cannot be a constant during the expansion of the universe, except for photons. When these components interact with the space-time background, particle production(annihilation) can occur. We study the influence of the interaction on the entropies of these components and obtain the conditions guaranteeing that the entropy of each component satisfies the second law of thermodynamics.
