A flow energy installation, in particular a wind power installation, having a housing which has a droplet-shaped cross section and can be adjusted about its vertical axis aligned with the flow direction, in particular the wind direction, wherein the housing has an inlet opening on the front face to an inner flow channel, which leads to at least one outlet opening which is arranged in particular at the side on the housing, and at least one axial incident-flow propeller is arranged in the flow channel, wherein the flow channel has boundary surfaces which run in a convex shape, in its inlet area adjacent to the inlet opening.