Abstract: Embodiments provide methods and apparatuses for filtering a fluid through a porous membrane, and more particularly, it provides filtration methods and apparatuses for tangential-flow filtration using Vibration Induced Dynamics (VID) with a spiral-wound membrane filter element. Embodiments provided herein induce vibration via rotation of an unbalanced inner tube within a central filtrate drain tube, via axial deformation of a substantially circular-cylindrical outer shell, or a combination thereof. Also disclosed herein are friction-reducing separator fabrics for interleaving with the membrane of a spiral-wound filter element.

Abstract: The present invention relates to the marine drilling risers and other submerged hulls, and methods and apparatuses for reducing vibration and drag in the drilling risers when they are beset by ocean currents, for instance elastic swivel devices for use in orienting a riser in a desired direction for boundary layer control applications.