Porous material

Claim 1

A VEHICLE DESIGNED TO BE DRIVEN THROUGH AN ENVELOPING FLUID INCLUDING AN OUTER SKIN OVER WHICH TURBULENCE IS LIKELY TO OCCUR DURING FORWARD MOTION OF THE VEHICLE, AT LEAST ONE PERMEABLE PARTIALLY EXPANDED EXPANDABLE CELL HONEYCOMB MEMBER POSITIONED IN SAID SKIN AND HAVING ONE SURFACE EXPOSED TO THE FLUID, SAID HONEYCOMB MEMBER INCLUDING A PLURALITY OF OPEN ENDED SUBSTANTIALLY UNOBSTRUCTED CELL PASSAGEWAYS, ONE OPEN END OF SAID PASSAGEWAYS BEING AT SAID EXPOSED SURFACE OF SAID HONEYCOMB MEMBER AND PROVIDING THE PASSAGEWAYS DIRECT COMMUNICATION WITH THE ENVELOPING FLUID, THE AXES OF ADJACENT PASSAGEWAYS BEING SUBSTANTIALLY PARALLEL AND THE CROSS SECTIONAL AREA OF CERTAIN OF SAID PASSAGEWAYS VARYING WITH RESPECT TO THE CROSS SECTIONAL AREA OF OTHER OF SAID PASSAGEWAYS TO PRODUCT A PERMEABILITY GRADIENT ACROSS THE SKIN OF THE VEHICLE WHEREBY THE FLOW RATE OF A FLUID PASSING THROUGH SAID CERTAIN AND SAID OTHER PASSAGEWAYS VARIES IN A GIVEN MANNER AND A CONDUIT WITHIN THE VEHICLE COMMUNICATING WITH SAID PASSAGEWAYS FOR PASSING BOUNDARY LAYER FLUID DRAWN INTO SAID PASSAGEWAYS WHEREBY TURBULENCE OVER SAID SKIN IS REDUCED.