Tag Archives: flow

Stalling On The Back Of A Duck

Watching the bird flying around Juanita Bay can bring out the aero guy in me.  I was watching some ducks flying across the water and coming in to land.  While the wings were working hard, it was also possible to see the feathers fluttering on the back of the duck just below the neck.  Clearly, the flow is separating in this location when they are maxing out the lift and the feather get disturbed by the separation.  Does anyone else but me care?  Probably not so maybe no one is even reading at this point!

Tufting The Wing

I didn’t notice this at the time but, while working my way through some shots of the Alice taxi trials, I realized that the port wing is tufted.  Tufting is a simple but effective way to see how the flow is behaving on a surface.  It does need to be recorded, though, so I then looked for the camera and saw the blister up on the side of the fuselage that must contain the camera.  I don’t know whether they have been paying attention to the flow visualization while doing taxi trials or not.  They have had flaps down as well as up but, without the nose off the ground, maybe there has not been anything significant to see.  They sure aren’t saying and have other things to address after some of the testing issues.

Patterns In The Sand

Another repeat of a previous theme.  Water flowing over the sand on a beach creates some interesting patterns.  The sand on Cannon Beach included a lot of very dark grains.  These made the visualization of the movement of the sand easy to do.  It also allowed you to see where the water was flowing deeper or shallower which helped when walking through the water running across the beach.

Snoqualmie Falls Is A Bit More Active Now

The recent months in the Pacific Northwest have been very wet.  It has felt like it was always raining and not just gentle rain but heavy rain on a regular basis.  This means that there is plenty of water in the mountains and the rivers coming out of the Cascades are heavy with flow.  I figured a trip up to Snoqualmie Falls was in order.  A few months back I had been up there when the flow over the falls was very low.

With the two power stations built in to the falls, the demands that they put on the water often mean that there is a lot less to go over the falls themselves.  Once the water levels get high, though, there is more than enough for everyone!  The falls were really raging.  The spray blowing up from the river was quite intense and, depending on which way the wind was blowing, you could either be quite dry or getting a deluge.

Since I made the visit, the weather hasn’t got any better.  I imagine that the falls have continued to be in full flow ever since.  Downstream, the river valleys have been in flood with the river levels all high.  Hopefully no one is suffering too much – those areas are prone to flooding anyway and they tend to be ready for it.

Drainage Patterns in the Sand

Walking along the beach at Tofino, you see some interesting patterns in the sand.  He movement of water across the sand causes various ridges in the surface.  There is also water draining down the beach from the land behind the beach.  This water gathers behind the ridges but ultimately needs to drain further.  When it finds a weak spot, it cuts through the ridge.  Once it does so, the water all flows through this breach and it starts to take some sand with it.  It expands the cut and then deposits the sand further down as it slows down again.  This can result in some cool formations in the sand.

Waves at Santa Cruz

wpid12773-AU0E4796.jpgWhile watching the surfers at Santa Cruz, I also was watching the waves. Photographing waves is immensely frustrating. You see a wave do something really cool and want to get a picture of that. However, the waves never do the same thing twice so you are constantly frustrated. However, I did focus on two aspects of the waves while there. The sun angle was behind the waves so, as they started to break, the light would shine through from behind making a lovely green color light up the water. I find this really attractive and often look for it while watching the sea.wpid12677-AU0E4492.jpg

The other interesting aspect is the way the water runs off the sand after the wave has run its course. The gentle undulations in the surface cause the most interesting patterns to develop. The water is coming from multiple directions so the interaction of the flows results in some fascinating shapes. Looking down on these from above, they become quite abstract.

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