Methods and mechanisms for fluid sealing are provided. The disclosed mechanisms include a tool having a cavity configured to form a toroidal vortex and a fluid sealing element to induce an azimuthal variation of the toroidal vortex (a “dynamic seal”). The fluid sealing element may include a sharp change in the axial symmetry of the cavity to induce the azimuthal variation. Some exemplary shapes of the fluid sealing element may include a notch in a cavity, a step shaped cavity, or an angular cavity in the tool. Methods for manufacturing such a dynamic seal is also provided as well as methods for producing hydrocarbons with a plunger having the dynamic seals. The tool may be a plunger, a pig, an in-flow control device, or other cylindrical device traveling through a conduit or tubular member.