Imagine a still pond at the edge of a forest. Make it a beautiful autumn day because that’s a nice thought. The surface is like smooth glass despite the rugged shape of the ground beneath it. This is because the surface of a fluid defines a zero potential height. Essentially the only forces acting on it are gravity and gravity is acting perpendicular to the surface. But what if you could include another force on the pond? How would the…
Turn on your faucet. Go on, I’ll wait. Make sure you keep the speed of the water low enough that the water still appears clear (i.e. laminar). Now consider the diameter of the stream near the faucet and then closer to the basin. You should notice that the stream thins as it flows down into the sink. How strange! Stream thinning is not just a quirk of your sink! It is, in fact, a consequence of the very fundamental law…
A diapir is region of lower density material (in this case salt) intruding into the overlying material. Salt Diapirs are formed through the slow process of evaporation, sedimentation, and compaction. A region experiences frequent flooding Subsequent evaporation will deposit salt The area is covered by later deposition where the overlying material will compact the deeper material. The density of the deeper sediment will increase while the density of salt is less affected by the pressure because of its crystal structure…
The Rossby Number describes the importance of the rotation of the frame on the flow. It is the ratio of the inertial force (e.g. buoyancy) of the fluid to the Coriolis force imposed by rotation. A larger Rossby number will mean the flow’s behavior is less dependent on the rotation. where describes the typical magnitude of the horizontal flow components, is the rotation rate, is the latitude of the fluid parcel on a sphere (e.g. Earth), f is the…
Reynold’s Number is a descriptive property of a flow that can help determine how heat and mass is transported. It is the ratio of the inertial to viscous force in the fluid (i.e. how fast is the flow moving relative to how viscous it is). Specifically, it can predict if a flow is laminar (smooth with little to no intersection between flow lines) or turbulent (chaotic with a lot of mixing of flow lines). A flow will transition between laminar and turbulent when…