Tornado-Borne Missile Speeds

To ensure the safety of nuclear power plants in the event of a tornado strike it is required that, in addition to the direct action of the wind and of the moving pressure field, the designer consider the impact of tornado-borne missiles, i.e., of objects moving under the action of aerodynamic forces induced by the tornado wind. It is, therefore, necessary that estimates be made of the speeds attained by potential missiles under such tornado wind conditions as are specified for the design of nuclear power plants. To calculate such speeds a rational model for the tornado-borne missile was proposed, based on the assumption that the missile tumbles during its flight, and a computer program was developed, based on this model. Missile trajectories and speeds were calculated corresponding to various assumptions regarding the initial conditions and the tornado wind field. The sensitivity of the results to changes in these assumptions was examined.