Gas pressure P_g, 0 at the inner boundary (z₀ = 1 kpc) of the flux tube for the wind background model Model W (full line) and the almost hydrostatic background Model H (dashed line) as a function of time. After 6 × 10⁶ yr the last SN exploded within the SB and we keep the values of the boundary values fixed. Every Δt_SN = 4.8 × 10⁵ yr and amount of 0.9 E_SN = 0.9 × 10⁵¹ erg is added to increase P_g, 0. The CR pressure P_c, 0 increases by the usage of 0.1 E_SN at every SN explosion. The lower panels exhibit the mass loss by the galactic wind, that is, Ṁ₀ = A₀ρ₀u₀ and the velocity at u₀. We note that during the phase of repeating SN explosions, Model H generates higher mass loss rates because the winds expand into a more tenuous medium than Model W.