Tag: hydraulic jump

Looking at the picture above, taken in the South Walney Island Nature Reserve on our walk yesterday, what is the first thing you notice? For me, it is not the cute little hide which is a perfect spot for seal and bird watching, for me it is — obviously! — what is going on with […]

Last stop on my work trip that — apart from doing important work, obviously — brought me to Berlin for some wave watching and to Brodowin to look at beaver dams: Eberswalde. Waiting for an appointment, I sat in the sun next to this adorable little waterfall and looked at so many nice examples of […]

— This post was written for “Teaching in the Academy” in Israel, where it was published in Hebrew! Link here. — Many times students fail to see the real-life relevance of what they are supposed to be learning at university. But there is an easy way to help them make the connection: Ask them to take […]

A very convenient way to describe a flow system is by looking at its Froude number. The Froude number gives the ratio between the speed a fluid is moving at, and the phase velocity of waves travelling on that fluid. And if we want to represent some real world situation at a smaller scale in […]

The other day I found the perfect standing waves on a current: This egg-carton-like pattern really stays pretty constant over time and I think the changes in the wave pattern are mostly due to changes in the sand bed below! You see the sharp edge that is currently being eroded, and sometimes you catch bits […]

Looking at a creek on a Sunday stroll, and seeing lots and lots of concepts from hydrodynamics class. For example below, you see waves radiating from each of the ducks. And you see interference of waves from all those ducks. What happens if the ducks bring their waves closer? At some point, all those waves from […]

This is a method that I have been excited about ever since learning about #birdclass in the “Evidence-based undergraduate STEM teaching” MOOC last year: Help students discover that the content of your class is not restricted to your class, but actually occurs everywhere! All the time! In their own lives! The idea is that students take […]

Hydraulic jumps, especially submerged ones, are a very theoretical concept for many students, one that occurs in a lab experiment if they are lucky, but more likely only seems to exists in videos, drawings, and text books. But we can observe them all the time if we know what we are looking for! They don’t only […]

The most impressive hydraulic jump might be in the Denmark Strait, but there are others around, too! [deutscher Text unten] When filling the big wave tank with a hose, we can see a hydraulic jump. Of course, the flow field isn’t mainly controlled by hydraulics, but still we see the Froude number changing from greater […]

Standing waves caused by rocks in a current. I am incredibly fascinated by standing waves. The standing waves are caused by rocks sitting in a current. From the pictures below it is not really clear where those rocks are situated, whether they are upstream of all this wave action or in the focal point of […]

Wind waves on one side of the current – no waves on the other. Recently in Bergen, I was walking to meet up with a friend at the kayak club, and I had to cross a bridge that has always fascinated me. Underneath the bridge, there is only a very narrow opening connecting basically the […]

More movies of my kitchen sink. I am really fascinated by the hydraulic jumps in my kitchen sink. I can’t believe I haven’t used this before when I was teaching! Yes, movies of rivers and rapids are always really impressive, too, but how cool is it to be able to observe hydraulic jumps in your […]

Water changing its velocity from above to below the critical velocity. Recently in beautiful Wetzlar: The river Lahn flows through the city below the medieval cathedral at sunset. And I’m showing you this because we can observe a hydraulic jump! A hydraulic jump occurs when water that was flowing faster than the critical speed suddenly […]