Secular change in the orbital parameters caused by hydrodynamic force for a prograde WD with M = 0.21 M_⊙ and P_b = 9 h under different accretion rate. Top panel shows the change in β, the specific angular momentum, and the specific orbital energy caused by drag force. It also shows the effect on β caused by gravitational radiation for comparison. The dashed black line represents the point with Ṁ_Acc of GSN 069 and e = 0.95, it predicts $\dot{\beta }/\beta \approx -3.5\times {10}^{-4}{\mathrm{yr}}^{-1}$(see texts). Bottom panel represents the change in a and e relative to β.