Friday, July 3, 2009

Truth and noise

We were briefly looking at some wing-body join issues and decided to talk about modeling related to fairings which would be part of the exterior design. Remember that the recent problem dealt with the internal structure which can be analyzed and tested statically; the external configuration would impact performance in the air.

Now, since we didn't have specifics, some general issues can be addressed. One deals with noise which could be of several types, such as from representational mismatches. Modeling grapples with this type of thing all the time. Knowing about the information and data that is involved is an integral part of any knowledge state.

Many times, truth is both contextual and situational, even if we consider what we can know of the big-t issues. Hence, an operational viewpoint can be our most effective means which then brings up processing which then, in the modern times, involves computation (which is becoming ubiquitous).

Ah, that little thing has grown to be very problematic and will continue to be such.

So, we can assume that a fairing would need to be smooth to reduce complications related to drag. What would smooth mean?

Well, the concept is not unlike what people are used to. Smoothness can be determined by senses; even sight can be used, as a smooth surface is appealing to the eyes in certain circumstances. For instance, the polished look relates to smoothness.

How is the idea of smoothness expressed on the computer via model? Well, it's not as easy as one might think. But, again, a lot of work has gone into this. Let's just say that one has to deal with changes with time (the concept of the derivative in calculus).

For those who drive, you probably heard that applying pressure steadily to the accelerator (which you press to move) so that you have a 'smooth' increase in speed helps with mileage. If you graphed the change in speed, you could then see how well your foot's action worked.

But, consider what would happen if you hit the accelerator in a spastic (perhaps, random) fashion. The car would jerk as it changed speed (up and down) trying to respond to your foot. Of course, there would be low mileage; but, any progress toward the destination would be very slow.

Let's look at an example that isn't specific to wing-body joining but applies nevertheless.


09/13/2009 -- Will look further into the necessity of the sandbox.

08/20/2009 -- Note 1: 'Derivative(s)' has been used a few times in the posts. The context may imply the usage, hopefully. But, in general, we're talking two types. 1) from finance, where 'derived from' is the proper interpretation (or as one may surmise from posts here and elsewhere, something from nothing). 2) the usual mathematical variety.

Modified: 08/24/2011

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