Leading Edge Contamination :
Leading edge contamination (LEC) is the classical problem of transition noted right at the leading edge of a swept back wing. This was noted during and immediately after the second world war and remained intractable since then. This is due to the inability of classical linear instability to explain this phenomenon. The attachment line shear layer is known to be more stable then attached zero pressure gradient shear layer and the linear theory predicts just the opposite behaviour. It is for this reason, leading researchers in the field have termed it also as a bypass transition. In the following two published paper this transition phenomenon is studied parametrically and a plaussible physical model has been proposed.