“…Unfortunately, such claims by inventors that they have "beaten Betz" have only served to give DWTs a bad reputation. Many studies have investigated the feasibility and associated augmentation factors seen in DWTs in an effort to further their development (Hu and Cheng, 2008;Igra, 1976Igra, , 1984Hansen et al, 2000;Werle and Presz Jr., 2008;van Bussel, 2007;Oman et al, 1977;Leoffler Jr. and Vanderbilt, 1978;Ohya et al, 2002Ohya et al, , 2008Politis and Koras, 1995;and Jamieson, 2009) with the largest prediction of 7 by Badawy and Aly (2000); however, conclusions have been quite varied. Werle and Presz Jr. (2008) used fundamental momentum principles and concluded that the possible augmentation factor could only approach 2 and that earlier studies had incorrect assumptions, leading to overly optimistic predictions.…”