Measurement of reflection of traveling waves near the onset of binary-fluid convection

Abstract

We present direct experimental measurements of the reflection coefficient r and of the group velocity s for traveling-wave convection in a binary fluid. We measure the dependence of r and s on the separation ratio ψ. Theory predicts that, for small enough ‖ψ‖, r should vary as ‖ψ${\mathrm{\Vert }}^{1/2}$. This dependence was not found. Instead, the value of r is almost constant over the range -0.136<ψ<-0.0096. We conjecture that the variations in concentration near the cell’s end walls due to the traveling waves are responsible for the discrepancy.