Inhalers with fins that deagglomerate dry powder using inspiratory effort of a user of an inhaler. The inhaler fins, at least in steady state conditions, are configured to generate dry powder and airflow patterns having turbulence with flow vortices, some of which may have a vortex having an axis of rotation that extends in an inspiratory flow direction while others may have a vortex that is substantially orthogonal to the inspiratory flow direction in an inspiratory airflow path, as an amount of dry powder travels through the inhaler to thereby deagglomerate the dry powder without trapping undue amounts of the dry powder during inhalation.