JoVE Science Education
Mechanical Engineering
A subscription to JoVE is required to view this content.
Source: Alexander S Rattner and Sanjay Adhikari; Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA
Objects, vehicles, and organisms immersed in fluid mediums experience forces from the surrounding fluid in the form of buoyancy- a vertical upward force due to fluid weight, drag- a resistive force opposite the direction of motion, and lift- a force perpendicular to the direction of motion. Prediction and characterization of these forces is critical to engineering vehicles and understanding the motion of swimming and flying organisms.
In this experiment, the balance of buoyancy, weight, and drag forces on submerged bodies will be investigated by tracking the rise velocity of air bubbles and oil droplets in a glycerin medium. The resulting drag coefficients at terminal rise velocities will be compared with theoretical values.
1. Fabrication of gas injection test section (see schematic and photograph, Fig. 2)
A series of rising air bubbles and oil droplets of varying diameters are presented in Fig. 3. The small bubbles and droplets rise at lower velocities due to relatively stronger drag forces. At these low velocity and length scales, strong surface tension forces result in nearly spherical bubbles and droplets. The largest bubbles approach Re ~ 2, resulting in somewhat flattened tails in the wake region. The largest oil droplets only approach Re ~ 0.2 due to thei
This experiment demonstrated the measurement of drag coefficient for rising bubbles and droplets in a fluid medium. Drag coefficients were determined by accounting for weight, buoyancy, and drag forces. Results were compared with a theoretical model for bubble/droplet CD at low Reynolds numbers.These results could be directly applicable to the design of industrial heat and mass exchangers, such as steam generators in power plants. In steam generators, vapor bubbles must be removed from the heated area
Skip to...
Videos from this collection:
Now Playing
Mechanical Engineering
29.5K Views
Mechanical Engineering
21.5K Views
Mechanical Engineering
20.7K Views
Mechanical Engineering
57.3K Views
Mechanical Engineering
7.7K Views
Mechanical Engineering
40.5K Views
Mechanical Engineering
27.8K Views
Mechanical Engineering
24.5K Views
Mechanical Engineering
15.5K Views
Mechanical Engineering
13.4K Views
Mechanical Engineering
11.0K Views
Mechanical Engineering
10.6K Views
Mechanical Engineering
7.1K Views
Mechanical Engineering
22.5K Views
Mechanical Engineering
25.8K Views
ISSN 2578-7829
Copyright © 2025 MyJoVE Corporation. All rights reserved
We use cookies to enhance your experience on our website.
By continuing to use our website or clicking “Continue”, you are agreeing to accept our cookies.