EXP 1-4 Measurement Data and Results: Difference between revisions
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=Axisymmetric drop impact dynamics on a wall film of the same liquid= | =Axisymmetric drop impact dynamics on a wall film of the same liquid= | ||
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The '''drop-film interaction in the three experimental videos''' (see Table 1 in Section [[ | The '''drop-film interaction in the three experimental videos''' (see Table 1 in Section [[EXP 1-4 Description]]) can be characterized as follows. | ||
* 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 late stage, capillary waves propagate on the surface of the film without formation of a notable central dome. | * 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 late stage, capillary waves propagate on the surface of the film without formation of a notable central dome. | ||
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Latest revision as of 10:01, 17 August 2023
Axisymmetric drop impact dynamics on a wall film of the same liquid
Measurement data/results
The drop-film interaction in the three experimental videos (see Table 1 in Section EXP 1-4 Description) can be characterized as follows.
- 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 late stage, capillary waves propagate on the surface of the film without formation of a notable central dome.
- For the moderate energy impact a rising crown is formed at the boundary between the residual and the initial film where there is a kinematic discontinuity due to the jump in both the film thickness and the local velocity field. The crown ascend continues as long as the inertial forces dominate the surface tension forces. The upper free rim of the crown remains stable and fully axisymmetric and the case corresponds to the crown formation without break-up regime. In the late stage after collapse of the crown, a dome like structure forms at the impact center without generation of a jet.
- The case of the high energy impact corresponds to the crown formation without break-up regime as well. However, the increased magnitude of inertial forces causes the crown to grow much higher (approximately twice) as compared to the moderate energy impact. While the upper free rim remains axisymmetric during the ascend of the crown, slight deviations from axisymmetry can be noticed during the collapse of the crown. Moreover, the energy of the impact is high enough to form a central Worthington jet which emerges from the impact center. The central jet experiences rupture (pinch-off) and forms satellite droplets. These droplets bounce on the surface of the disturbed film before merging into it.
The time evolution of the three characteristic crown dimensions in experiment and simulation is provided via Excel files for the moderate and high impact energy cases. These Excel files are available for download through the website https://tudatalib.ulb.tu-darmstadt.de/handle/tudatalib/3295.2. The data in the Excel file for the case with moderate impact energy are displayed in Fig. 7. There, experimental results for the three crown dimensions (base diameter, rim diameter, crown height) are compared with numerical results obtained for the two surface tension models and different grid resolutions. The Excel file 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 experimental crown dimension and four columns for the respective numerical results obtained with the different resolutions.
The content of the Excel file for the case with high impact energy is equivalent. An illustration similar to Fig. 7 for the high energy impact can be found in Bagheri et al. (2022), where also more detailed discussions of the experimental and numerical results are provided. It is concluded that the relaxation model for surface tension is able to reproduce the experimental data for all impact energies with reasonable accuracy irrespective of the number of interfacial cells, in contrast to the equilibrium model.
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
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
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