Get["C:\Users\Administrator\Desktop\...\data.mx"]
hx = Derivative[1, 0][mdfun]; (*get the first derivative with respect to x*)
hxxx = Derivative[3, 0][mdfun];  (*get the third derivative with respect to x*)
scaledA[d_, B_, k_, e_, hx_, h_, hxxx_] := (-3*d*(1 + B*k) *hx )/((k + h + B*k*h^3*e) - 3*1/e*hxxx - 3*1/e*hx;
A = scaledA[1, 1, 0.1, 0.05, hx[x, 6], mdfun[x, 6], hxxx[x, 6]]; (*calculate a term of stream function*)
scaled[Phi][A_, z_, h_, B_, k_, hx_, e_, m_] := A*(z^3/6 - (h*z^2)/2) + m ((1 + B k)*k*hx*z^2)/((k + h + B k h)^2*e); (* stream function *)

sl = ContourPlot[scaled[Phi][A, y, mdfun[x, 6], 1, 0.1, hx[x, 6], 0.05, 1] == Range[0.1, 1.3, 0.2],{x, 0, 2*Sqrt[2] [Pi]}, {y, 0, mdfun[x, 6]}, ImageSize -> 400,ContourStyle -> {
Directive[Black, Thin],
Directive[Black, Thin],
Directive[Black, Thin],
Directive[Black, Thin],
Directive[Black, Thin],
Directive[Black, Thin],
Directive[Black, Thin]
}, Frame -> False, (*PerformanceGoal[Rule]"Speed"*)] (*plot seven streamlines *)

asl = sl /. Line[x_] :> {Arrowheads[{{0.02, 0.2}, {0.02, 0.4}, {0.02, 0.6}, {0.02, 0.85}}], Arrow[x]}