One way of obtaining this solution is to look for a cylindrically symmetric perfect fluid solution in which the fluid exhibits " rigid rotation ".
12.
Sonic black holes are possible because phonons in perfect fluids exhibit the same properties of motion as fields, such as gravity, in space and time.
13.
Among the perfect fluids other than dusts or radiation fluids, by far the most important special case is that of the static spherically symmetric perfect fluid solutions.
14.
Among the perfect fluids other than dusts or radiation fluids, by far the most important special case is that of the static spherically symmetric perfect fluid solutions.
15.
In the latter case, the equation of state of the perfect fluid may be used in Friedmann Lema�tre Robertson Walker equations to describe the evolution of the universe.
16.
In a subsequent article, Mbarek and Paranjape showed that it is in fact possible to obtain the required deformation through the introduction of the energy-momentum of a perfect fluid.
17.
These criteria can often be useful for spot checking alleged perfect fluid solutions, in which case the coefficients of the characteristic are often much simpler than they would be for a simpler imperfect fluid.
18.
In general relativity, the "'Wahlquist fluid "'is an exact rotating perfect fluid solution to Einstein's equation with equation of state corresponding to constant gravitational mass density.
19.
There is in fact a known perfect fluid solution, the Wahlquist fluid, which is Petrov type D and which has a definite surface across which one can attempt to match to a vacuum exterior.
20.
The Friedmann equations can be easily solved in presence of a perfect fluid with equation of state ( ideal gas law ) http : / / en . wikipedia . org / wiki / Friedmann _ equations
