The concept of surface tension doesn't seem to be well explained in the first course on Fluid Mechanics. Fundamentals of Fluid Mechanics writes
There are a few things that are causing me problems:A tensile force may be considered to be acting in the plane of the surface along any line in the surface. The intensity of the molecular attraction per unit length along any line in the surface is called the Surface Tenison .
- The analogy tensile force is quite hard to understand, I mean the force of attraction looks something like this . As you can see, the molecules at the top have no upward force acting on them and therefore they form something like a surface (this what others writes). Well, okay there is no upward force but we can certainly go for superposition of forces and from the diagram, we can see that the upper molecule should accelerate downwards but it doesn't, why? How all this have any correlation with tension? (the way I have understood tension till now is the force that a string exerts on an object connected to it).
- The phrase along any line in the surfaceis causing problems because it writes in the surface not on on the surface which is quite hard to comprehend what the book intends.