Jay, I know what kind of model you meant, they are used in weather forecasting every day.
Some are. That is not the only application of CFD, nor is it particularly representative of the strength or fidelity of CFD. We routinely build CFD models that very faithfully represent the actual measured effects.
We now have actaul data (allegedly) and no longer need the model.
I disagree. The numerical models and other things help us understand the observations in the photographs and videos.
I am having a hard time understanding why the soil is so unaffected....ie the probe soil displacement along with the little mound of soil built up on the inside of the pad that has been pointed out.
I agree you're having a hard time. That's the problem.
For example, why do you think the exhaust traveled flat across the ground? I explained what happens to a plume when it hits a flat surface. If you had internalized that explanation, you would realize that the bulk of the plume dispersal would have been above the footpad and therefore not very eligible to drastically affect a pile of dirt under the lip of the footpad.
You mentioned 2500 lbs of thrust at touchdown. I'd be willing to venture to say on 11 it was a little more.
I wouldn't. In order to maintain a constant descent rate (i.e., hover) the computer has to constantly reduce the throttle setting as fuel is consumed. The amount of thrust necessary to hold a descent rate is equivalent to the lunar weight of the spacecraft and its fuel. Fuel is the single biggest mass-contributing element to an Apollo spacecraft. Apollo 11 landed with practically dry tanks. That means it would have landed with the lowest hover thrust of any of the missions.
Either way, 2500 lbs is a significant blast.
Compared to ... ?
They were kicking up some serious dust when they landed.
Compared to ... ?
The picture anomaly I am still at odds with is the fact the soil from the probe has spilled over and on top of the print.
Why is this anomalous given the scenario I described?
I merely am questioning (same horse) how and why the dust you use as your evidence, appears to be undisturbed by the thrust of the LEM as it landed.
I provided an explanation. You simply expressed disbelief in it.
I just look at the dust displacement during landing from alleged actual videos.
Did you talk to any of the pilots? They'll tell you what they saw in three dimensions, that the grainy flat films don't show.
That horse is in the barn unless someone has an answer an ignorant dunce like myself can understand.
Whether you're an "ignorant dunce" or not is irrelevant. If that condition exists, it can be remedied -- but only with your cooperation.
Notwithstanding, it is not generally true that fully explicative answers are necessarily comprehensible to the layman. The explanation is the explanation; whether you understand it is up to you. If the explanation requires a detailed understanding of fluid dynamics, and you don't have that understanding, then any explanation we could offer would be either incomplete or incomprehensible to you.
...and the ascent engines visible affect on the flag is a valid point to the horse we are talking about.
No. It isn't.
It Merely points out the fact the exhaust is significant.
No. The APS is almost half again more powerful than the DPS at hover. It also ignites ten feet from the surface and the plume impinges on an irregular platform.
A nylon flag is affected by even the slightest breeze. Compacted cohesive regolith is comparatively unaffected. The Apollo 11 flag was blown over by the hot-fire test of the RCS. That's how easy it is to blow over one of those flags.
You cannot quantitatively compare the APS to the DPS. You cannot quantitatively compare a flag to a compacted regolith.
I guess my attitude here comes from when I talk to people about this, they have been so brainwashed into believing the exhaust was a gentle cushion of air that had little affect on the soil.
Most of the people I have heard argue this can cite fluid dynamics computations or first-order approximations of them that support their beliefs. Those who argue it was a tremendous blast offer only unquantified comparisons of dubious fidelity. Which would you consider more brainwashed?
The affect of the thrust on the flag (3500lbs) is significant to demonstrating to common folk like myself exactly what is happening here.
But it's not exactly what is happening in the descent. It just bears enough resemblance to it in order to appeal to the layman.
You base your beliefs on data that is understandable to you, I base mine on data that is understandable to me.
Sensible, but since my data and my understanding of it are the same that are used to engineer these mechanisms in the first place, and yours is admittedly based on your lay analysis, which of us is more likely to be closer to the truth?
Pictures go along way with me and the guy from NASA said, "Tell them the proof is in the photos". A statement that resonated within my soul so here I am.
Good for you. Now what are you willing to do in order to understand what you see in the photos? Welch didn't necessarily intend that the photos simply be looked at casually by laymen without consulting other materials. The proof may or may not be in the photographs. But if it is, extracting that proof is not necessarily a task for the casual investigator.
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