Brassel Byron P, Maharaj Sunil D, Goswami Rituparno
Astrophysics Research Centre, School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa.
Entropy (Basel). 2021 Oct 25;23(11):1400. doi: 10.3390/e23111400.
We consider the energy conditions for a dissipative matter distribution. The conditions can be expressed as a system of equations for the matter variables. The energy conditions are then generalised for a composite matter distribution; a combination of viscous barotropic fluid, null dust and a null string fluid is also found in a spherically symmetric spacetime. This new system of equations comprises the energy conditions that are satisfied by a Type I fluid. The energy conditions for a Type II fluid are also presented, which are reducible to the Type I fluid only for a particular function. This treatment will assist in studying the complexity of composite relativistic fluids in particular self-gravitating systems.
我们考虑耗散物质分布的能量条件。这些条件可以表示为物质变量的方程组。然后，能量条件被推广到复合物质分布；在球对称时空中还发现了粘性正压流体、零尘埃和零弦流体的组合。这个新的方程组包含了I型流体所满足的能量条件。还给出了II型流体的能量条件，该条件仅对于特定函数可简化为I型流体。这种处理将有助于研究复合相对论流体特别是自引力系统的复杂性。
