“…ψ = 0 • ), giving rise to counter-rotating vortices. Recent works provide further quantitative data for broad cones (Imayama, Alfredsson & Lingwood 2012, 2013Kato, Alfredsson & Lingwood 2019a;Kato et al 2019b). However, such detailed experimental data on slender cones have up to now not been available.…”