EXP 1-4 Introduction

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

Introduction

This contribution is based on the publication by Bagheri et al. (see reference below), where the normal impact of a single drop onto a wall film of the same liquid is investigated experimentally and numerically. Droplet impact onto wetted surfaces is of pertinence to many technical applications such as internal combustion engines, automotive exhaust gas after-treatment, icing on plane wings and spray coating technologies to name a few. Immediately after the impact, the droplet expands radially along the surface. If the impact kinetic energy is sufficiently high, an upward growing crown is generated with detachment of secondary droplets.

For the cases considered here, splashing is absent and the drop-film interaction is axisymmetric. The two-phase flow is laminar and its dynamics is governed by an interplay between inertial, viscous and capillary forces. The formation and expansion of the crown and the associated flow field in both phases are illustrated in Fig. 2 showing results of numerical simulations. Experimental videos of the drop-film interaction are provided for download in Section Lib:EXP 1-4 Description. From these videos, experimental data for the time evolution of the three characteristic dimensions of the crown are extracted, namely the height of the crown and its top and base radius (see Section Lib:EXP 1-4 Measurement Quantities and Techniques.).

Fig. 2: Snapshots of phase distribution and velocity field from axisymmetric numerical simulations (moderate drop impact velocity 2 m/s).

The present test case is based on the 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

and the underlying research was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) within the CRC/TRR 150 Turbulent, chemically reactive, multi-phase flows near walls, project number 237267381. https://www.trr150.tu-darmstadt.de/der_sonderforschungsbereich/index.en.jsp

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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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