A method for the recovery of hydrocarbon from a reservoir includes arranging a chamber in fluid communication with the reservoir via at least one conduit. The chamber includes first and second wall parts movable relative to each other. An impact pressure is provided in the fluid to propagate to the reservoir via the conduit, where the impact pressure is generated by a collision process between an object arranged outside of the fluid and the first wall parts for the first wall part to impact on the fluid in the chamber. The chamber is arranged to avoid a build-up of gas-inclusions where the first wall part impacts on the fluid. This may be obtained by arranging the conduit in or adjacent to the zone where the gas-inclusions naturally gather by influence of the gravitational forces, or by placing the first wall part impacting on the fluid away from this zone.