Liquid-vapor pulsating flow in a vertically placed U-shaped miniature tube is investigated numerically. The two scaled ends of the U-shaped tube are the evaporator sections and the condenser section is located in the middle of the tube. The governing equations, obtained by analyzing the conservation of mass, momentum, and energy of the liquid and vapor Plugs, are nondimensionalized and the pulsating flow is described by five nondimensional parameters. The numerical solution is obtained by employing an implicit scheme. The effects of various nondimensional parameters on the performance of the pulsating heat pipe were investigated. The empirical correlations of the amplitude and circular frequency of oscillation were also obtained.