Apparatus with a controllable surface for underwater boundary flow

A controllable fluid-contacting surface apparatus comprising:

• (a) an underwater vessel comprising a propulsion source;
• (b) a flexible membrane having a water-contactable outer surface;
• (c) multiple electromagnetic actuators, each including a compliant electrode embedded in the membrane;
• (d) an electronic controller comprising programmable software, the controller being electrically connected to the actuators, and the controllers and the membrane being coupled to and movable with a portion of the vessel other than the propulsion source;
• and
• (e) the actuators being adapted to vary a shape of the membrane.

Computer software stored in non-transient memory, the software comprising:

• (a) instructions obtaining fluid-flow data from sensors;
• (b) instructions automatically determining a desired fluid-contacting shape of a flexible membrane based at least in part from (a);
• (c) instructions changing an energization state of multiple actuators to vary an actual fluid-contacting shape of the membrane based on at least one of:
• (a) water salinity, (b) water density, or (c) water waves.

A controllable fluid-contacting surface apparatus comprising:

• (a) a flexible membrane having a water-contactable outer surface;
• (b) multiple electromagnetic actuators, each including an output shaft;
• (c) the output shafts being coupled to the membrane and being adapted to vary a shape of the membrane by moving the output shafts substantially perpendicular to a water-flow direction against the outer surface of the membrane;
• and
• (d) fasteners encapsulated within the membrane, the fasteners being coupled to the output shafts.