Axisymmetric rotational stagnation point flow impinging on a radially stretching sheet

•Rotational stagnation-point flow impinging on a radially stretching surface.•Flow governed by stretch rate to strain rate ratio β.•Large beta asymptotics are presented.•Wall shear stress is calculated.•Dual solutions are found.•Linear temporal stability analysis of dual solutions is performed.

The normal impingement of the rotational stagnation-point flow of Agrawal (1957) [8] on a sheet radially stretching at non-dimensional stretch rate β is studied. A similarity reduction of the Navier–Stokes equations yields an ordinary differential equation which is solved numerically over a range of β  . A unique solution exists at the turning point β=βtβ=βt and dual solutions are found in the region β>βtβ>βt where βt=−0.657βt=−0.657 is the turning point in the parametric shear stress curve separating upper from lower branch solutions. An analysis of solutions near the Agrawal point β=0β=0 is provided, and the large-β asymptotic behavior of solutions is determined. Sample velocity profiles along both solution branches are presented. A linear temporal stability analysis reveals that solutions along the upper branch are stable while those on the lower branch are unstable.