Whatever

[Penguin]

I did a lot of earlier work on SAR radar algorithm technology and I was wondering how much you (penguin) know about the various E.M modes that govern a ship as to the reason for "dimpling" as seen on the DDG-1000 (I have a good idea as to why...just wondering about your take on it, I foresee an interesting conversation).

@Nilgiri: Do I read correctly that you suggest the dimpling is on purpose and serves are particular purpose in RCS reduction? Or is that interpretation on my part?

 

[Nilgiri]

@Nilgiri: Do I read correctly that you suggest the dimpling is on purpose and serves are particular purpose in RCS reduction? Or is that interpretation on my part?

No not for primary purpose but for an added mitigation (of certain RCS modes) once you decide you need to create a non-monolithic surface (for the various reasons discussed regarding surface stresses, fabrication etc - which I believe are the primary drivers).

It has been a long time since I touched the subject, but I remember reading about various backscatter phenomenon and coupling resonances (given the mirroring of the sea/air interface) that many radars these days are attuned to in post-processing...so I can definitely see a role for structuring the "dimples" a certain way (given a ship has to fabricated from components at some level) while having overall macro angular surfaces (for the main retro mitigation + specular enhancement modes everyone immediately associates "Stealth" with).

 

[Penguin]

No not for primary purpose but for an added mitigation (of certain RCS modes) once you decide you need to create a non-monolithic surface (for the various reasons discussed regarding surface stresses, fabrication etc - which I believe are the primary drivers).

It has been a long time since I touched the subject, but I remember reading about various backscatter phenomenon and coupling resonances (given the mirroring of the sea/air interface) that many radars these days are attuned to in post-processing...so I can definitely see a role for structuring the "dimples" a certain way (given a ship has to fabricated from components at some level) while having overall macro angular surfaces (for the main retro mitigation + specular enhancement modes everyone immediately associates "Stealth" with).

If dimpling/buckling is unavoidable, then making sure that its effects do not contribute to larger RCS (or even positively contribute to smaller RCS) through structuring the dimples would seem a good thing. But, I'm no engineer ;-)

 

[Blue Marlin]

@Penguin how you doing,

whats the name of the british company that designs aip submarines , not bae systems.

 

[Penguin]

@Penguin how you doing,

whats the name of the british company that designs aip submarines , not bae systems.

BMT?
http://www.bmtdsl.co.uk/bmt-design-portfolio/bmt-vidar-submarines/
https://en.wikipedia.org/wiki/BMT_Limited

@Blue Marlin: Sweating! (it is a very nice warm day today, will in the 20s centigrade. (Approaching 'skirt day' weather quality ;-)

 

[Blue Marlin]

BMT?
http://www.bmtdsl.co.uk/bmt-design-portfolio/bmt-vidar-submarines/
https://en.wikipedia.org/wiki/BMT_Limited

@Blue Marlin: Sweating! (it is a very nice warm day today, will in the 20s centigrade. (Approaching 'skirt day' weather quality ;-)

cheers

id image penguins would love the sun, over here the weather is great. 22c with a slight breeze perfect, but about an hour ago the clouds came in was planning on a bbq, dont know what to do

 

[Penguin]

cheers

id image penguins would love the sun, over here the weather is great. 22c with a slight breeze perfect, but about an hour ago the clouds came in was planning on a bbq, dont know what to do

I've barbequed from underneath an umbrella, and in the dark using a flash light. Also burned up an old wooden fence in the process. If you have a party tent, cover the BBQ and eat indoors.

The BBQ must go on!

http://redshed.co.uk/blog/10-ways-still-outdoor-bbq-rainy-day/

Be creative!

Although ...

 

[Nilgiri]

If dimpling/buckling is unavoidable, then making sure that its effects do not contribute to larger RCS (or even positively contribute to smaller RCS) through structuring the dimples would seem a good thing. But, I'm no engineer ;-)

I am thinking someone analysed the effects of using longer wavelengths with enough post processing (esp available as computational power has increased significantly) and figured out (with final in-situ validation) the utility of the tradeoff between mie resonances at regular microwave range that would be in play with the panel size/dimple geometry...and rayleigh for longer wavelengths (and thus lower effective RCS of the body at those ranges given higher effective diffusivity and lower amounts of other modes) that would be introduced because of the "dimpling".

It would ultimately depend on the summation of all the modes that operate at each range (Esp with low incidence angle reflection the water provides which will act as another retro mode). Thus having a perfectly planar, continuous surface next to a refractive medium interface (sea/air) I think actually creates backscatter modes (among others) that need to be accounted for passively.

Basically you inherit a situation and make the best of it for each regime (i.e might as well make it more resistant to detection at longer wavelengths rather than pure optimisation at lower wavelengths which would call for large perfectly planar, continuous surfaces...which are difficult to fabricate and maintain anyway in a non-ideal world with other forces at play).

When you don't have this issue of a refractive medium interface, the issue drops greatly (i.e the mode channels)....and you can optimise much more effectively depending on which modes dominate. Hence we wouldn't see as much utility of having a slightly dimpled (panel-based) surface for aircraft or spacecraft which are enveloped in entire homogeneous mediums. Aircraft of course have major aerodynamic considerations anyway that preclude this significantly to begin with.

This was the line of thinking (there could easily be others...I am no high level theory expert, I worked on materials application mostly) I ruminated on when it came up in the earlier thread....when claimed it was something totally unrelated to the RCS....when I think its much more complicated and involved than that.

I will have to look up later if there is any paper in the open domain about what I am speculating here though....it would need a large number of real world testing + validation which I doubt are non-classified.

@Vergennes @Taygibay

Do we know any real radar ppl in this forum anywhere btw?

 

[MastanKhan]

https://www.facebook.com/video.php?v=807721696048536

 

[Taygibay]

Do we know any real radar ppl in this forum anywhere btw?

@Picdelamirand-oil

 

[Taygibay]

So Whatever means whatever, right? Even stuff that
isn't whatever is allowed cuz... m'well, really whatever?

Actually, never mind, as the kids oversay, but if it ever
gets decided that on-topic ( mil stuff ) is off-topic in the
Whatever threads, I was the first if not only one to troll thus!!!

​

- - - - - » » [ TAY ]

 

[Picdelamirand-oil]

@Picdelamirand-oil

No I am not a specialist in Radar, I am a specialist in complex systems. Normally I dialogue with specialists in different fields who participate in the realization of a complex system and I seek the best compromise and deduces the allocation of performance in each area.

 

[Taygibay]

So that in effect, you likely own the best combo
of knowledge and understanding on and of radar
on PDF.

I'm sorry if my trust in your abilities hurts your
humility but I'll stand by my answer.

You're the closest thing to a specialist we've got,
mon brave homme.

Je parierais ma virilité contre un cent de melons
que tu fais une transformée de Fourier plus vite
que moi, et pourtant j'y tiens!

AND : https://defence.pk/pdf/threads/the-rafale-hidden-beauties-and-its-future.422896/

Salut, Tay.

 

[friendly_troll96]

Nomi bhai (friendly troll) ne meri post ko thank kiya hai... it means maine zaroor koi maarfat ki baat kahi ho gi


Oh nahi yaar... meri divorce se acha hai Allah aap ko is duniya se hi utha le

was cleaning up my scrapbook and found some old gems of whatever.
can't stop laughing.
ain't deleting this one.

too bad can't thank you again.

 

[The Eagle]

@The Eagle can you please unban me from that thread (I do like to interact with Burmese defense members there), i wont use that language out of the blue, sorry.

I am really sorry for late reply but didn't get notification of this post at all, trust me.