Flow device and methods of creating different pressure drops based on a direction of flow

A flow device includes a flow-through region comprising at least one stage having a pocket configured to create a first pressure drop across the flow-through region in response to flow through the flow-through region in a first direction and a second pressure drop in response to flow through the flow-through region in a second direction. The first pressure drop is less than the second pressure drop under the same flow rates. The flow device has no moving parts to create the difference in pressure drop between the first direction and the second direction, the pocket has a larger cross sectional flow area than a first opening and a second opening fluidically connected to the pocket and a baffle positioned within the pocket having a "U" shape with a concave side of the baffle facing toward the second opening.