  We study the laminar and turbulent channel flow over a viscous hyper-elastic
wall and show that it is possible to sustain an unsteady chaotic turbulent-like
flow at any Reynolds number by properly choosing the wall elastic modulus. We
propose a physical explanation for this effect by evaluating the shear stress
and the turbulent kinetic energy budget in the fluid and elastic layer. We vary
the bulk Reynolds number from 2800 to 10 and identify two distinct mechanisms
for turbulence production. At moderate and high Reynolds numbers, turbulent
fluctuations activate the wall oscillations, which, in turn, amplify the
turbulent Reynolds stresses in the fluid. At very low Reynolds number, the only
production term is due to the energy input from the elastic wall, which
increases with the wall elasticity. This mechanism may be exploited to
passively enhance mixing in microfluidic devices.
