Comparison between calculated P v and observed (thin solid-blue lines) line profiles of HD 14947. Upper panel: effect of the number of clumps. The purple line with crosses is calculated with d = 0, r_cl = 1, m = 0.1, and L₀ = 0.5. The green line with triangles and the red line with squares differ only by L₀ = 0.2 and L₀ = 0.1, respectively. The thick solid black line is calculated with r_cl = 1, m = 0.1, L₀ = 0.5, and d = 0.2. The dotted orange line is from the PoWR model and corresponds to a smooth wind. Lower panel: effect of the onset of clumping and the interclump medium density. The green line with triangles is calculated with d = 0, r_cl = 1.1, m = 0.1, and L₀ = 0.5. The red line with asterisks differs only by d = 0.1, while the thick solid black line is for d = 0.2 so it differs against the thick solid black line in the upper panel only by the different r_cl = 1.1. The remaining clump parameters are fixed as given in Table 4.