Change environmental envelope for wavefield to permit more challenging variations

[M1chaelM]

Current State

Currently our technical guide limits values of the gain / peak period per the following diagram:

This diagram is generated from 5 sample points, as follows:	peak period	gain
1	1.0
2	1.0
4	0.5
6	0.39?
8	0.39?

Problems

• Limiting the gain to 1.0 prevents us from testing choppier water, which is a significant challenge in real world applications, especially relating to perception.
• The diagram is not very clear about the allowed gain values for higher periods, and limiting gain to a fine-grained value just below 0.4 seems a bit bizarre.

Proposed Solution

Change the envelope to use the following values:	peak period	gain	explanation
1	2.0	chosen to create challenging choppy water conditions
2	2.0	chosen to create challenging choppy water conditions
4	1.0	arbitrary interpolation; needs to be tested
6	0.6	arbitrary interpolation; needs to be tested
8	0.4	rounded up for clarity

Explanation

The values for peak period 1 and 2 have been chosen through qualitative assessment of their impact on the simulation. The value for peak period 8 is just rounded up to be more clear. Values for peak period 4 and 6 are arbitrary guesses interpolating between the other values and need to be tested to make sure they aren't too severe.

[M1chaelM]

Additional note

Once the new envelope is specified, practice worlds need to be adjusted so that 0, 1 and 2 use appropriate values that demonstrate the range of possible conditions. We need to do this in our practice worlds so teams aren't surprised by competition conditions.

[M1chaelM]

@caguero Since this effects our competition documentation, I think it should be attached to the 2.3.0 release. Do you agree?

[M1chaelM]

Period 2, gain 2.0:

[M1chaelM]

Period 4, gain 1.0:

These values look a bit extreme to me, and I noticed at least one crash, so I think the gain needs to come down further.

[M1chaelM]

Period 4, gain 0.8:

The qualitative change between gain of 1.0 and 0.8 is dramatic. This looks like a much more reasonable maximum value for period 4.

[M1chaelM]

Period 6, gain 0.8:

Period 6, gain 0.6:

I tested period 6 with gain of 0.8 and 0.6. Both produce reasonable effects, and the difference between them is fairly subtle, so I think we should go with 0.8 as the top of the envelope. A gain of 0.6 is a little more mellow but nothing prevents us from choosing this value if we want that.

[M1chaelM]

Period 8, gain 0.8:

Period 8, gain 0.6:

Period 8, gain 0.4:

From the tests above, it looks like gain of 0.4 is still a good maximum for period 8. Anything higher causes the water to wash over the docks and is probably out of range for this competition.

[M1chaelM]

Conclusion:

Based on qualitative assessments above, I think our new envelope values should be:

peak period	gain
1	2.0
2	2.0
4	0.8
6	0.8
8	0.4

@caguero, @j-herman and @tejalbarnwal could you take a look at the above and see whether you anticipate any problems with this change? I will generate a new diagram.

[M1chaelM]

New diagram:

[M1chaelM]

This is now included in version 1.2 of the technical guide.