Shape evolution of free falling deformed droplets

2015 ◽  
Vol 60 (10) ◽  
pp. 917-921
Author(s):  
Yuan LI ◽  
Zhen CHEN ◽  
XingGuo GENG ◽  
XiaoPeng CHEN ◽  
DuYang ZANG ◽  
...  
Keyword(s):  
2017 ◽  
Vol 828 ◽  
pp. 374-394 ◽  
Author(s):  
Sten A. Reijers ◽  
Jacco H. Snoeijer ◽  
Hanneke Gelderblom

When a free-falling liquid droplet is hit by a laser it experiences a strong ablation-driven pressure pulse. Here we study the resulting droplet deformation in the regime where the ablation pressure duration is short, i.e. comparable to the time scale on which pressure waves travel through the droplet. To this end, an acoustic analytic model for the pressure, pressure impulse and velocity fields inside the droplet is developed in the limit of small density fluctuations. This model is used to examine how the droplet deformation depends on the pressure pulse duration while the total momentum to the droplet is kept constant. Within the limits of this analytic model, we demonstrate that when the total momentum transferred to the droplet is small the droplet shape evolution is indistinguishable from an incompressible droplet deformation. However, when the momentum transfer is increased the droplet response is strongly affected by the pulse duration. In this later regime, compressed flow regimes alter the droplet shape evolution considerably.


2017 ◽  
Author(s):  
Ashly Senske ◽  
◽  
Claire Marvet ◽  
Sultan Akbar ◽  
Silishia Wong ◽  
...  

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1041
Author(s):  
Mazhar Hussain ◽  
Mattias O’Nils ◽  
Jan Lundgren

High temperatures complicate the direct measurements needed for continuous characterization of the properties of molten materials such as glass. However, the assumption that geometrical changes when the molten material is in free-fall can be correlated with material characteristics such as viscosity opens the door to a highly accurate contactless method characterizing small dynamic changes. This paper proposes multi-camera setup to achieve accuracy close to the segmentation error associated with the resolution of the images. The experimental setup presented shows that the geometrical parameters can be characterized dynamically through the whole free-fall process at a frame rate of 600 frames per second. The results achieved show the proposed multi-camera setup is suitable for estimating the length of free-falling molten objects.


2021 ◽  
Vol 385 ◽  
pp. 1-11
Author(s):  
Rodrigo Xavier de Almeida Leão ◽  
Leandro Silva Amorim ◽  
Marcio Ferreira Martins ◽  
Humberto Belich Junior ◽  
Enrico Sarcinelli ◽  
...  

2021 ◽  
pp. 102076
Author(s):  
Robert Winkler ◽  
Jason D. Fowlkes ◽  
Philip D. Rack ◽  
Gerald Kothleitner ◽  
Harald Plank

2009 ◽  
Vol 9 (11) ◽  
pp. 4700-4705 ◽  
Author(s):  
Masaharu Tsuji ◽  
Yoshinori Maeda ◽  
Sachie Hikino ◽  
Hisayo Kumagae ◽  
Mika Matsunaga ◽  
...  
Keyword(s):  

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1331
Author(s):  
Massimiliano Pieraccini ◽  
Lapo Miccinesi ◽  
Neda Rojhani

Step-frequency continuous-wave (SFCW) modulation can have a role in the detection of small unmanned aerial vehicles (UAV) at short range (less than 1–2 km). In this paper, the theory of SFCW range detection is reviewed, and a specific method for correcting the possible range shift due to the Doppler effect is devised. The proposed method was tested in a controlled experimental set-up, where a free-falling target (i.e., a corner reflector) was correctly detected by an SFCW radar. This method was finally applied in field for short-range detection of a small UAV.


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