Nesavršeni fluidni kozmološki modeli bianchijevog tipa V s tokom topline

We obtain two classes of exact solutions to the Einstein\u27s field equations by applying a special law of variation of the Hubble\u27s parameter for a Bianchi type V space-time in the presence of an imperfect fluid with both shear and bulk viscosities together with heat flow. The coefficient of the shear viscosity is determined on the basis of the physical assumption that it is proportional to the Hubble\u27s expansion parameter, whereas the bulk viscosity coefficient is determined when the energy-density and the kinetic pressure satisfy the barotropic equation of state. These classes of solutions represent expanding cosmological models with and without a finite physical singularity. The physical and kinematical features of the models in two types of cosmologies are discussed.Izvodimo dvije vrste točnih rješenja Einsteinovih jednadžbi polja primjenom posebne ovisnosti Hubbleovog parametra u Bianchijevom prostoru-vremenu tipa V, uz pretpostavku nesavršenog fluida i prisustvo posmične i volumne viskoznosti i izmjene topline. Koeficijent posmične viskoznosti se određuje pretpostavkom da je razmjeran Hubbleovom parametru širenja, a koeficijent volumne viskoznosti uvjetom barotropske ravnoteže gustoće energije i kinetičkog tlaka. Te vrste rješenja predstavljaju kozmološke modele sa širenjem svemira i s početnom fizičkom singularnošću ili bez nje. Raspravljaju se fizikalne i kinematske odlike dvaju modela