Anyone shed light on strange shock formation?

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  • Last Post 01 May 2020
Mattobox posted this 01 May 2020

Making an air intake, and I've got a shock forming where I certainly don't think it should be, resulting in my simulation being... bad to say the least.

This is what my simulation looks like currently: https://imgur.com/a/AtmtGIj

I'm planning for the three ramps to give oblique shocks, normal shock in the central bit, and diffuse out to the outlet at the end. This is pretty much exactly what I'm going for: https://imgur.com/a/5te0trA

I've deduced that it is the proximity of that top part of intake to the bottom part that causes this big normal shock to occur where its not supposed to. When I moved it twice as far away, the oblique shocks formed normally. The weird part is, in the 'target' image above, based on their dimensions, their two parts were closer together than mine were?

Can anyone see a reason why this proximity would result in this? Its also pretty strange that whilst the shock is formed by the top part I'd assume since its movement affects whether it forms or not, it forms considerably ahead of it. I'm pretty desperate. Could it be something to do with the constriction of area? I've done some thinking and have no idea.

The thing is I don't know where to go from here, since the residuals aren't bad so this does seem to be the result of the setup I have: I just have no idea why its happening

Thanks for any help,

Matt

rahkumar posted this 01 May 2020

Hello, 

What are your inlet parameters and the boundary conditions used? Please check your geometric dimensions and also could you insert an image of the geometry which would help in better visualizing the simulation? 

Regards,

Rahul 

Regards, Rahul

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