34,587 research outputs found
Quantum Fluctuations of Black Hole Geometry
By using the minisuperspace model for the interior metric ofstatic black
holes, we solve the Wheeler-DeWitt equation to study quantum mechanics of the
horizon geometry. Our basic idea is to introduce the gravitational mass and the
expansions of null rays as quantum operators. Then, the exact wave function is
found as a mass eigenstate, and the radius of the apparent horizon is
quantum-mechanically defined. In the evolution of the metric variables, the
wave function changes from a WKB solution giving the classical trajectories to
a tunneling solution. By virtue of the quantum fluctuations of the metric
evolution beyond the WKB approximation, we can observe a static black hole
state with the apparent horizon separating from the event horizon.Comment: 18 pages, DPNU-93-3
Turbulent boundary layer around a group of obstacles in the direction of flow
Results of an investigation of a boundary layer in a turbulent flow on the surface of a wall having a group of obstacles on the path of flow are presented with regard to the mean velocity field, velocity distribution of the two dimensional flow, wall surface shear stresses and Reynolds stresses measured in a downstream cross section where an interference of boundary layers takes place in a flow around adjacent obstacles arranged on the path of flow
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