The transient spread of a circular liquid jet and hydraulic jump formation

Abstract The transient flow of a circular liquid jet impinging on horizontal disk, and the hydraulic jump formation, are examined theoretically numerically. interplay between inertia gravity is particularly emphasised. governed by thin-film equations, which solved along with force balance across jump. unsteadiness caused linearly accelerating from an initial to final steady state. To validate predicted boundary-layer evolution, analytical development conducted for small distance impingement, time. In addition, predictions film profile location compared against numerical simulation flow, further validated experiment flow. evolutions thickness wall shear stress in developing region found be similar those reported fluid lying stretching surface. responds acceleration quasi-steadily near impingement but exhibits long-term behaviour Analysis evolution considered range 5 < Fr 40 Froude number (based radius velocity). For 10, reaches state instantly when ceases. At higher number, settles at later time, exhibiting overshoot due dominance inertia.