From turtle2@u.washington.edu Thu Apr 17 11:43:33 1997 Received: from jason05.u.washington.edu (jason05.u.washington.edu [140.142.78.6]) by lists.u.washington.edu (8.8.4+UW96.12/8.8.4+UW97.03) with ESMTP id LAA19040 for ; Thu, 17 Apr 1997 11:43:32 -0700 Received: from homer13.u.washington.edu (homer13.u.washington.edu [140.142.70.14]) by jason05.u.washington.edu (8.8.4+UW96.12/8.8.4+UW97.03) with ESMTP id LAA16246; Thu, 17 Apr 1997 11:43:30 -0700 Received: from localhost (turtle2@localhost) by homer13.u.washington.edu (8.8.4+UW96.12/8.8.4+UW97.03) with SMTP id LAA92760; Thu, 17 Apr 1997 11:43:30 -0700 Date: Thu, 17 Apr 1997 11:43:29 -0700 (PDT) From: Lorna Fitzpatrick To: "C.E. Graduate Students" cc: PEMM Program , pemm@u.washington.edu Subject: CEWA 520 Seminar - April 22, 1997 (fwd) Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII CEWA 520 Seminar Tuesday, April 22, 1997 More 220, 3:30 p.m. Professor John R. Chaplin City University, London Flow Around a Horizontal Cylinder Beneath Waves, and Energy Extraction The flow around a horizontal cylinder beneath waves, aligned with its axis parallel to the wave crests, is surprisingly complex. Steady streaming generates circulation around the cylinder to produce lift that may be comparable in magnitude with inertia forces. But the streaming is weaker than the predictions of two-dimensional flow modelling because an instability generates radial plane jets which roll up to form hoop vortices around the cylinder. Flow visualisations and velocity measurements by Laser Doppler Anemometry and Particle Image Velocimetry reveal this motion, and force measurements indicate a strong increase in non-linear loading as the cylinder is brought closer to the free surface. Spinning the cylinder on its axis increases the lift in a controllable way. Placing two parallel contra-rotating cylinders on a common central axis forms the basis of a wave energy device, the 'Wave Rotor'. Measurements of the performance of a model of this device in the laboratory are shown to be in reasonable agreement with analytical predictions. John --------------------------------------------- From January 9 to August 26, 1997: Department of Civil Engineering University of British Columbia 2324 Main Mall, Vancouver B C, Canada V6T 1Z4 Tel: (604) 822-2826 (direct) (604) 822-2637 (department) Fax: (604) 822-6901 .