Experimental study of interaction between a vortex ring and a solid surface for a wide range of ring velocities

2014 ◽  
Vol 21 (5) ◽  
pp. 561-565
Author(s):  
V. V. Nikulin
Keyword(s):  
Experimental Study ◽  
Vortex Ring ◽  
Solid Surface ◽  
Wide Range

scholarly journals Is contact angle a cause or an effect? – A cautionary tale

2020 ◽  
Vol 146 ◽  
pp. 03004
Author(s):  
Douglas Ruth
Keyword(s):  
Contact Angle ◽  
Solid Surface ◽  
Contact Angles ◽  
Two Dimensions ◽  
Experimental Results ◽  
Flow In Porous Media ◽  
Two Dimensional ◽  
Wide Range ◽  
Fluid Drop ◽  
Surrounding Fluid

The most influential parameter on the behavior of two-component flow in porous media is “wettability”. When wettability is being characterized, the most frequently used parameter is the “contact angle”. When a fluid-drop is placed on a solid surface, in the presence of a second, surrounding fluid, the fluid-fluid surface contacts the solid-surface at an angle that is typically measured through the fluid-drop. If this angle is less than 90°, the fluid in the drop is said to “wet” the surface. If this angle is greater than 90°, the surrounding fluid is said to “wet” the surface. This definition is universally accepted and appears to be scientifically justifiable, at least for a static situation where the solid surface is horizontal. Recently, this concept has been extended to characterize wettability in non-static situations using high-resolution, two-dimensional digital images of multi-component systems. Using simple thought experiments and published experimental results, many of them decades old, it will be demonstrated that contact angles are not primary parameters – their values depend on many other parameters. Using these arguments, it will be demonstrated that contact angles are not the cause of wettability behavior but the effect of wettability behavior and other parameters. The result of this is that the contact angle cannot be used as a primary indicator of wettability except in very restricted situations. Furthermore, it will be demonstrated that even for the simple case of a capillary interface in a vertical tube, attempting to use simply a two-dimensional image to determine the contact angle can result in a wide range of measured values. This observation is consistent with some published experimental results. It follows that contact angles measured in two-dimensions cannot be trusted to provide accurate values and these values should not be used to characterize the wettability of the system.

Dynamics of Liquid Sheet Breakup in Splash Plate Atomization

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
G. Thunivumani ◽  
Hrishikesh Gadgil
Keyword(s):  
Solid Surface ◽  
Weber Number ◽  
Jet Impingement ◽  
Liquid Sheet ◽  
Force Balance ◽  
Impingement Angle ◽  
Wide Range ◽  
Perforated Sheet ◽  
Sheet Breakup ◽  
Regime Map

An experimental study was conducted to investigate the breakup of a liquid sheet produced by oblique impingement of a liquid jet on a plane solid surface. Experiments are carried out over a wide range of jet Weber number (80–6300) and various jet impingement angles (30 deg, 45 deg, and 60 deg) are employed to study the sheet dynamics. The breakup of a liquid sheet takes place in three modes, closed rim, open rim, and perforated sheet, depending upon the Weber number. The transitions across the modes are also influenced by the impingement angle with the transition Weber number reducing with increase in impingement angle. A modified regime map is proposed to illustrate the role of impingement angle in breakup transitions. A theoretical model based on force balance at the sheet edge is developed to predict the sheet parameters by taking the shear interaction between the sheet and the solid surface into account. The sheet shape predicted by the model fairly matches with the experimentally measured sheet shape. The breakup length and width of the sheet are measured and comparisons with the model predictions show good agreement in closed rim mode of breakup.

scholarly journals Improvement of Pump Performance at Off-Design Conditions

1985 ◽  
Author(s):  
J. Paulon ◽  
C. Fradin ◽  
J. Poulain
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
Mass Flow ◽  
Flow Characteristic ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Pump Performance ◽  
Wide Range ◽  
Mass Flows ◽  
Design Value

Industrial pumps are generally used in a wide range of operating conditions from almost zero mass flow to mass flows larger than the design value. It has been often noted that the head-mass flow characteristic, at constant speed, presents a negative bump as the mass flow is somewhat smaller than the design mass flows. Flow and mechanical instabilities appear, which are unsafe for the facility. An experimental study has been undertaken in order to analyze and if possible to palliate these difficulties. A detailed flow analyzis has shown strong three dimensional effects and flow separations. From this better knowledge of the flow field, a particular device was designed and a strong attenuation of the negative bump was obtained.

scholarly journals Strength Comparison of FDM 3D Printed PLA Made by Different Manufacturers

TEM Journal ◽  
2020 ◽  
pp. 966-970
Author(s):  
Damir Hodžić ◽  
Adi Pandžić ◽  
Ismar Hajro ◽  
Petar Tasić
Keyword(s):  
Experimental Study ◽  
Additive Manufacturing ◽  
Fused Deposition Modelling ◽  
Fused Deposition ◽  
Manufacturing Technique ◽  
Plastic Materials ◽  
Wide Range ◽  
3D Printed ◽  
The Difference ◽  
Printing Parameters

Widely used additive manufacturing technique for plastic materials is Fused Deposition Modelling (FDM). The FDM technology has gained interest in industry for a wide range of applications, especially today when large number of different materials on the market are available. There are many different manufacturers for the same FDM material where the difference in price goes up to 50%. This experimental study investigates possible difference in strength of the 3D printed PLA material of five different manufacturers. All specimens are 3D printed on Ultimaker S5 printer with the same printing parameters, and they are all the same colour.

scholarly journals An experimental study of the dynamics of ascent of the bubble system in the presence of a surfactant

2018 ◽  
Vol 194 ◽  
pp. 01002
Author(s):  
Alexandra Antonnikova ◽  
Sergey Basalaev ◽  
Anna Usanina ◽  
Eugene Maslov
Keyword(s):  
Experimental Study ◽  
Reynolds Numbers ◽  
Experimental Setup ◽  
Bubble Cluster ◽  
Bubble System ◽  
Wide Range ◽  
Compact Cluster ◽  
Glycerol Medium

This paper presents investigations on the new experimental setup for obtaining a compact cluster of monodisperse bubbles of a given diameter is presented. Also we provided the results of experimental study of the bubble cluster floating-up in the presence of a surfactant in a wide range of Reynolds numbers. There was held a comparison of the dynamics of the floating-up of a monodisperse bubble cluster in a glycerol medium and in the medium glycerin supplemented with a surfactant.

scholarly journals An experimental study of the molecular mixing process in an axisymmetric laminar vortex ring

1991 ◽  
Vol 3 (5) ◽  
pp. 1385-1392 ◽  
Author(s):  
Kenneth B. Southerland ◽  
John R. Porter ◽  
Werner J. A. Dahm ◽  
Kenneth A. Buch
Keyword(s):  
Experimental Study ◽  
Vortex Ring ◽  
Mixing Process ◽  
Molecular Mixing

Experimental Study of Machining of Smart Materials Using Submerged Abrasive Waterjet Micromachining Process

2018 ◽  
Author(s):  
Sagil James ◽  
Anurag Mahajan
Keyword(s):  
Experimental Study ◽  
Smart Materials ◽  
Thermal Stresses ◽  
Piezoelectric Materials ◽  
High Hardness ◽  
Machining Process ◽  
Critical Parameters ◽  
Abrasive Waterjet ◽  
Parameter Study ◽  
Wide Range

Smart materials are new generation materials which possess great properties to mend themselves with a change in environment. Smart materials find applications in a wide range of industries including biomedical, aerospace, defense and energy sector and so on. These materials possess unique properties including high hardness, high strength, high melting point and low creep behavior. Manufacturing of these materials is a huge challenge, particularly at the micron scale. Abrasive waterjet micromachining (AWJMM) is a non-traditional material removal process which has the capability of machining extremely hard and brittle materials such as glasses and ceramics. AWJMM process is usually performed with nozzle and workpiece placed in air. However, machining in the air causes spreading of the waterjet resulting in low machining quality. Performing the AWJMM process with a submerged nozzle and workpiece could eliminate this problem and also reduce noise, splash, and airborne debris particles during the machining process. This research investigates Submerged Abrasive Waterjet Machining (SAWJMM) process for micromachining smart ceramic materials. The research involves experimental study on micromachining of smart materials using an in-house fabricated SAWJMM setup. The effect of critical parameters including stand-off distance, abrasive grain size and material properties on the cavity size, kerf angle and MRR during SAWJMM and AWJMM processes are studied. The study found that SAWJMM process is capable of successfully machining smart materials including shape memory alloys and piezoelectric materials at the micron scale. The machined surfaced are free of thermal stresses and did not show any cracking around the edges. The critical process parameter study revealed that stand-off distance and abrasive grit size significantly affect the machining results.

Experimental study on secondary droplets produced during liquid jet impingement onto a horizon solid surface

2021 ◽  
Vol 120 ◽  
pp. 110249
Author(s):  
Yi Zhan ◽  
Yusuke Kuwata ◽  
Tomio Okawa ◽  
Mitsuhiro Aoyagi ◽  
Takashi Takata
Keyword(s):  
Experimental Study ◽  
Solid Surface ◽  
Jet Impingement ◽  
Liquid Jet ◽  
Secondary Droplets
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