Gravitational collapse of dissipative fluid as a source of gravitational   waves
  Gravitational collapse of cylindrical anisotropic fluid has been considered in analogy with the work of Misner and Sharp. Using Darmois matching conditions, the interior cylindrical dissipative fluid (in the form of shear viscosity and heat flux )is matched to an exterior vacuum Einstein--Rosen space-time. It is found that on the bounding 3-surface the radial pressure of the anisotropic perfect fluid is linearly related to the shear viscosity and the heat flux of the dissipative fluid on the boundary. This non-zero radial pressure on the bounding surface may be considered as the source of gravitational waves outside the collapsing matter distribution. 
Sanjukta Chakraborty and Subenoy Chakraborty
physics.gen-ph gr-qc