EXP 1-4 Measurement Data and Results

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

Measurement data/results

Excel files with experimental results for moderate and high impact velocity are available for download through the website https://tudatalib.ulb.tu-darmstadt.de/handle/tudatalib/3295 or via the following doi: https://doi.org/10.48328/tudatalib-722. In addition to the experimental results, the Excel files also include results of numerical simulations with a phase-field method. The content of the Excel files is described below.

In the numerical simulations, two different models for the surface tension force (equilibrium/relaxation) are employed in combination with different spatial resolutions. In the phase field method, the surface tension force is related to the profile of the phase-discriminating order parameter (C) and depends in particular on the gradient of C within the diffuse interface region. In the standard (equilibrium) formulation, C is assumed to follow the tanh profile of the equilibrium state whereas the relaxation model accounts for the deviation of the actual profile of C from the equilibrium profile. The spatial resolution is quantified by the number of mesh cells N_c used to resolve the diffuse interface as illustrated in Fig. 6.

Fig. 6: Initial phase distribution with magnified views of the diffuse interface for different grid resolutions employed in numerical simulations.

Fig. 7 compares experimental results for the three crown dimensions (base diameter, rim diameter, crown height) with numerical results obtained for the two surface tension models and different grid resolution for the case with moderate impact energy. In contrast to the equilibrium model for surface tension, the relaxation model is able to reproduce the experimental data with reasonable accuracy irrespective of the number of interfacial cells. The Excel file for this case includes one worksheet for each of the six subfigures of Fig. 7. Each of the six worksheets contains one column for time, one column for the respective measured (experimental) crown dimension and four columns for the respective numerical results obtained with the four different resolutions.

Fig. 7: Comparison of the crown base diameter, crown rim diameter and crown height with the experiment - moderate energy impact.

A similar Excel file is provided for the case with high impact energy. A figure similar to Fig. 7 but for the high energy impact can found in the reference below, where besides a detailed discussion of the experimental and numerical results also conclusions drawn from the comparison are provided.

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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