BobK,
Your model of Torrey cliffs seem like something a masters degree student at the university adjacent to the park could handle. I am guessing that topo-true models or data might be in the hands of the city or county or state regarding the cliffs already (as agents have had to deal with erosion, property construction permits, etc. The golf and real estate interests probably have had keen interest in precise measures, erosion rates, etc. Maybe data could be entered, as you suggest, it seems, to make a model and placed in extant windtunnels.

On similar note, a series of instrumented kite flights might be able to explore and record stations under various wind conditions and solar conditions; gradually a "feel" would be had. Maybe RC pilots could fly instruments that could record things to explore the realm in front of and below the cliffs at stations also. I often get a "feel" for wind flows just be releasing dandelion seeds, soap bubbles, thistle hair (?) without the seed. Smoke streams played as a recreational fitness activity could give a "feel" for what is occurring; release at sand and watch; release at different east-west points on the sand and watch. Then shooting wads of flour into 3D points that become of interest. Kite arches with aggregate stability could maintain while along the arch could be high-count multiple tailings that could give a "feel" for what is happening. Maybe a club of researchers dould just explore all kinds of ways to visualize and record notes and data and photos about the famous cliffs. First off would be to research just how much study has been done on turbulence profiles in front of cliffs at seashore; I imagine geologists for erosion sake may have done studies. All such combined with HG and PG pilot reports would help to advance the "feel" for cliffs' situation. The mixing, the reversals, the heated bubbles, and even the triggering effects of one's own flight on the bubbles are part of the adventure.
Since stringed-to-ground-non-free-flying kites (STGNFFK) are troublesome at Torrey while free-flying-string-kites (HG and PG) are flying with humans aboard, then using such STGNFFK tactics may not have much opportunity to fly for studies wanted; however shooting flour pops might be productive (sling shot?).
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Just received this note from Rick regarding sloughing thermals. I place his note here to join my attention on Torrey's cliffs' heated face at certain times of day and certain air conditions and wind conditions:

Hi Joe,

Your earlier post got me thinking about how to map out the flow of a site like Torrey. I think one possible way would be to have someone fly along the cliff trailing a line containing one or more smoke devices evenly spaced. Then someone could fly both behind and above with cameras to record the smoke trails as they interact with the cliff.

Of course, this is what we (as pilots) should be trained to do with our "mind's eye" when looking at any terrain in any wind conditions. We should always by trying to "see" what the air would do as it interacts with the ground. Your suggested mapping of the wind would be a great way to help train that "mind's eye" so that it more closely reflects ... God's eye.

Thanks as always for your thoughts. It's an honor to have you as such an active member of our little forum.

Bob Kuczewski

You have to wonder what sort of reaction the Billionares would have to pilots flying with smoke canisters around the mansions.

By the way, I've reviewed my original map, and I realized that the actual ridge line might not be clear to people who are not familiar with the site. So I've updated the map to show the ridge line and the area that might be in shadow from a 45 degree crosswind (northwest). The area with blue shading is routinely flown during west or even southwest winds, and it can provide very good lift. But if the wind was changing to include a strong northwest component (as the spikes in the history show) then this area might be subject to mechanical turbulence from both the cliff and trees which are directly upwind.

I said I thought it was one possible way ... not the most likely or even best way.   

I've inserted the wind chart as an inset into the map to make a more self-contained diagram of what I think might have happened.

The information is already contained and described in the other diagrams in this topic, but I'm posting this combined diagram in case anyone wants to post it to another forum. If you do post it elsewhere, please include a link back to this topic ( "http://ushawks.org/forum/viewtopic.php?f=4&t=1031" ).

Thanks.



P.S. I've also added this image to a post on paraglidingforum.com.

Miscellany:



windward reverse-flow eddy

airflow patterns upwind of steep cliffs

flow fields in front of obstacles

Assume wind is hitting the Torrey cliffs as a barrier (flow from ocean to land); let the point of reference be a glider in front of the cliffs while the PIC is concerned about airflow events in front of the cliffs. What is the steepness and height of the cliff? What is the condition of the wind that is approaching the cliffs (speed, temperature, gustiness, ). What angle is the wind relative to the face of the cliffs? What conditions will bring on reverse-flow eddies seaward of the cliff's face below the top of the cliff? How large might those seaward reverse-flow eddies be? Who has had interest in such flows in front of sea cliffs (sailors, kite flyers, gliding-kite pilots, soil-erosion scientists, ...)? How might Torrey soarable-days flows become very well known and visualized? May we look for onboard real-time visualization to add to our inner-eye skills. Canopy-only gliders have a bit more to worry about as regards these matters.

Those are a lot of good questions Joe. I'm sorry, but I don't have many answers. It would be interesting to fly a kite from the beach with multiple wind streamers along the line. But it would be difficult to get that kite up from the beach (where the wind is pretty minimal).

But I can try to help the mind's eye a little bit by providing a better diagram of the terrain. So I sketched in some very rough contour lines from my own memory of that area. The blue line represents the top of the cliff which is fairly level, and the yellow lines are my approximations of the contours (this is just an approximation!!).



Here's the terrain according to Google. I tried to zoom it in, but this is as far as it would go. From my experience with those cliffs, the Google terrain lines do not seem accurate ... but that may be a misperception on my part.



Maybe these contour lines will help you with the visualization of the flow.

A surfer reported that he saw the wing collapse. The lifeguards heard a loud noise that they described as an impact. It seems that many assume that the noise was that of the pilot hitting the cliffs (the lifeguards did not see it). Having heard a paraglider recover from a frontal collapse with a loud bang myself, I suspect that the pilot had a collapse and during the process of recovering got turned towards the cliffs or was already pointed at terrain. The collapse recovery produced the loud noise and then the pilot impacted the terrain at flying speed, maybe even pendulum rocked into the terrain due to the momentum from the loss of altitude. The collapse recovery might have been at nearly the same time as the impact, which makes it appear that the pilot hitting the cliffs made the noise.

From your wind and terrain notes, BobK,
there could be very significant horizontal/oblique vortex streams created which have their sideways, downwards, and upwards vectoring. Dynamic plummeting of a wing can occur, regardless of the airframe or not; canopy-only could have a quick collapse. The edges from comfort lift to really full collapse when meeting an oblique or horizontal helicity would not be nice.