https://doi.org/10.1351/goldbook.09899
Cross-sectional area of the empty tube: \(A_{\rm{c}} = \pi r_{\rm{c}}^{2} = \pi (d_{\rm{c}}/2)^{2}\), where \(d_{\rm{c}}\) is the column diameter.
Cross-sectional area of the empty tube: \(A_{\rm{c}} = \pi r_{\rm{c}}^{2} = \pi (d_{\rm{c}}/2)^{2}\), where \(d_{\rm{c}}\) is the column diameter.