1. Department of Fluid Mechanics, LABSON, Technical University of Catalonia, Colom 7, 08222 Terrassa, Spain
2. Department of Electrical Engineering, Technical University of Catalonia, Colom 1, 08222 Terrassa, Spain
3. Department of Mechanical Engineering, LABSON, Technical University of Catalonia, Colom 7, 08222 Terrassa, Spain