Valveless Pumping with an Unsteady Stenosis in an Open Tank Configuration
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis paper examines the beneficial role of an unsteady stenosis, operating without the use of any external energy source, as a means for augmenting the flow rate of a valveless pump in a hydraulic loop, including an open tank.
The pressure amplitudes along the flexible tube increased towards the rigid-flexible tube junction (as a result of the wave reflections) which were found to be significantly attenuated by the presence of the stenosis.
The following are comments:
1. The introduction part as well as summary of references should be improved. The novelty of this present study should be illustrated. The differences between the previous paper, ref 6 may be given as well.
2. Some of details are referred to the work of reference 6, https://www.mdpi.com/2311-5521/8/9/249. However, the quality of this manuscript should be improved. A figure like what the authors have shown in ref 6 may helps the presentation of this manuscript. Figure of experimental devices, or schematic diagram.
3. Some details: the texts in figure 1 is too difficult to recognize. Please revise.
4. Figures may be improved for a higher quality, the scale bars in figure 2 should be highlighted.
5. Units or parameters in figure 4, 8, should be presented.
6. The red line in figure 7 is different with the others, double peaks as well as the phase shift was discussed. What is the reason?
7. What can we learn from this study, for application in many other similar pump industries?
Author Response
Please see the attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors
Extending from a prior experimental study, this manuscript further investigated the experimental configurations to augment the flow rate of a valveless pump in a vertical hydraulic loop by implementing artificial unsteady stenosis. While this research is of general scientific interest, there are a few aspects that need to be addressed:
- It is stated that the system “operating without the use of any external energy source, as a means for augmenting the flow rate”
This statement is not completely correct. It is necessary to evaluate the energy input to apply the unsteady pinching actions (compress and decompress) from an external source to operate the system.
- Typo on page 1 line 18: “ The role of the stenosis role was”
- Literature review is too thin. More information should be provided. What is the current stage of development in the field, what are the applications. Are there many other work in this field, what is their findings, what is the challenges, etc.
- Literature review should provide a context of the significance of the research. How the technology can be used? what are the potential applications.
- Figure 1: text font in the figure is too small.
- Page 2 line 55, it is necessary to present the Figure 2 [6] here, if it is part of the experimental setting for this manuscript as well.
- Is the stenosis device operated manually or automatically?
- Can any relationship be derived between pinching frequency, compression ratio and flow rate?
- Figure 2-10, legends need to be added to all these figures to distinguish different testing cases
- Figure 2, can you explain the trend of the curves, what is the relationship between net flow rate and pinching frequency, why the trend alters when frequency increase.
- Y-axis labels are missing for Figure 4, 7, 8
- What is the limitation in the study?
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors have made sufficient revisions and can be accepted.
