EXP 1-4 Description

Axisymmetric drop impact dynamics on a wall film of the same liquid

Front Page

Introduction

Review of experimental studies

Description

Experimental Set Up

Measurement Quantities and Techniques

Data Quality and Accuracy

Measurement Data and Results

Description of Study Test Case

A sketch of the general set-up of the experiment and the geometry is shown in Fig. 3 in Section Lib:EXP 1-4 Experimental Set Up while the principal quantities measured are given in Section Lib:EXP 1-4 Measurement Quantities and Techniques.

The liquid used in the experiments is silicone oil (density ρ = 920 kg/m³, kinematic viscosity ν = 5 ⋅ 10^-6 m²/s, surface tension σ = 0.0177 N/m) and the ambient gas is air (density 1.2 kg/m³, kinematic viscosity 1.52 ⋅ 10^-5 m²/s). The film height h = 500 μm as well as the drop diameter D = 1.5 mm are kept fixed, resulting in the dimensionless film thickness δ = h/D = 0.33. The drop velocity U is varied from 1 to 3 m/s. Accordingly, the Weber number We = ρDU²/σ is in the range 78 – 702 while the Reynolds number Re = DU/ν is in the range 300 – 900.

For each impact velocity a video is provided for download in Table 1. The meaning of the file names is as follows: S5 = silicon oil viscosity 5 mm^2/s, D1p5 = drop diameter 1.5 mm , H500 = film height 500 µm. The digit after U denotes the drop impact velocity in m/s, e.g. U3 = 3 m/s.

Table 1: Investigated drop impact velocities

Impact energy	Impact velocity	Weber number	Reynolds number	Video for download
Low	1 m/s	78.0	300	Download S5_D1p5_H500_U1
Moderate	2 m/s	311.9	600	Download S5_D1p5_H500_U2
High	3 m/s	701.7	900	Download S5_D1p5_H500_U3

For the low energy impact the drop joins the liquid film smoothly without formation of a rim or crown. In this deposition regime, the drop spreads on the surface of the liquid film forming a disk-shaped structure. In the later stage, capillary waves propagate on the surface of film without formation of a dome like structure.

Further details on the test case can be found in the following publication:

M. Bagheri, B. Stumpf, I.V. Roisman, C. Tropea, J. Hussong, M. Wörner, H. Marschall, Interfacial relaxation – Crucial for phase-field methods to capture low to high energy drop-film impacts, Int. J. Heat Fluid Flow 94 (2022) 108943, https://doi.org/10.1016/j.ijheatfluidflow.2022.108943

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Contributed by: Milad Bagheri, Bastian Stumpf, Ilia V. Roisman, Cameron Tropea, Jeanette Hussong, Martin Wörner, Holger Marschall — Technical University of Darmstadt and Karlsruhe Institute of Technology

Front Page

Introduction

Review of experimental studies

Description

Experimental Set Up

Measurement Quantities and Techniques

Data Quality and Accuracy

Measurement Data and Results

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