A gas turbine engine and combustor assembly including a combustor liner defining therein a combustion chamber for the downstream flow of a main fluid. At least two axially spaced apart annular trapped vortex cavities are located on the combustor liner and staged axially and radially spaced apart. A cavity opening is located at a radially inner end of each of the at least two annular trapped vortex cavities. A plurality of injectors are configured tangentially relative to circular radially outer wall extending between an aft wall and a forward wall of each cavity to provide for an injection of air and fuel to form an annular rotating trapped vortex of a fuel and air mixture within a respective annular trapped vortex cavity. The annular rotating trapped vortex of the fuel and air mixture at the cavity openings is substantially perpendicular to the downstream flow of the main fluid.