1University of British Columbia, Vancouver, British Columbia, Canada
2Institute of Ocean Sciences, Sidney, British Columbia, Canada
3University of Alberta, Edmonton, Alberta, Canada
The stability of stratified shear flows with a density interface much thinner than the velocity interface has been studied theoretically, numerically and experimentally. When the interfaces are centered about the same level linear stability analysis and numerical simulations predict the Holmboe instability. Unfortunately attempts to reproduce this instability in mixing layer facilities have not been successful, because it is difficult to avoid a displacement between the two interfaces. Here we report on exchange flow experiments where the interfaces are centered about each other and Holmboe instabilities are observed. The results are compared with numerical simulations. We also compare numerical and laboratory experiments where there is a displacement between the two interfaces