Th e expansion section of a rocket nozzle is oft en conical in shape, and because the fl ow diverges, the thrust derived from the nozzle is less than it would be if the exit velocity were everywhere...

Th e expansion section of a rocket nozzle is oft en conical in shape, and because the fl ow diverges, the thrust derived from the nozzle is less than it would be if the exit velocity were everywhere parallel to the nozzle axis. By considering the fl ow through the spherical section suspended by the cone and assuming that the exit pressure is equal to the atmospheric pressure, show that the thrust is given by