The interest rate i is the the product of velocity V and Surplus value S = 1-u.
V*S = V*(1-u) converges at equilibrium to V*(1-u) = R where R is real investment demand.
Writing f’ = df/dt,
R = Q’/Q where Q is the real product. The interest rate i = V*(1-u) converges to a value i = R as V and 1-u converge to equilibrium values.
When a central bank sets an interest rate, that rate acts as a new initial value i(0).
For lower values of i(0), the range of oscillation is shifted to the right, in the direction of higher S = 1-u
(lower u) and lower velocity V.