#Request: Proper Bow Shock (at least visually)

30 messages · Page 1 of 1 (latest)

atomic pelican
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I guess I don't get to post links in the first post.

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Maybe it was too many pictures

main-qimg-d44e59bdfcb70a3d483cf4c336b41e16-c.jpg 255960main_A-28916-3ratio_946-710.jpg Schematic-of-a-capsule-type-reentry-vehicle-in-a-hypersonic-flow-field-adapted-from-Ref.png
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It'd be cool if it fed back into heating, but I understand that's probably asking too much

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In case anyone wants to jump into this rabbit hole:
https://en.wikipedia.org/wiki/Boundary_layer
https://ntrs.nasa.gov/citations/19930089669
https://ntrs.nasa.gov/citations/19710069971
https://ntrs.nasa.gov/citations/20205010736

Boundary layer

In physics and fluid mechanics, a boundary layer is the thin layer of fluid in the immediate vicinity of a bounding surface formed by the fluid flowing along the surface. The fluid's interaction with the wall induces a no-slip boundary condition (zero velocity at the wall). The flow velocity then monotonically increases above the surface until...

Heat-transfer and Pressure Distribution on Six Blunt Noses at a Mac...
NACA Conference on High-Speed Aerodynamics. A Compilation of Papers...

This document contains reproductions of technical papers presented by staff members of the NACA Laboratories at the NACA Conference on High-Speed Aerodynamics held at the Ames Aeronautical Laboratory of the NACA, March 18, 19, and 20, 1958. The primary purpose of the conference was to convey to the military services and their contractors the res...

Pterodactyl: Aerodynamic and Aerothermal Modeling for a Symmetric D...

NASA’s Pterodactyl project has investigated a deployable atmospheric entry vehicle integrated with a flap control system that provides precision targeting during reentry. The control system consists of eight flaps mounted at the edge of a heatshield that can deflect in and out of the flow. An aerodynamic and aerothermodynamic analysis process wa...

chrome coral
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Shock Cone*

atomic pelican
atomic pelican
# chrome coral Shock Cone*

A shock cone may be the more specific term for the one sub/supersonic phenomenon in one specific example photo, but it absolutely does not cover the broader phenomenon I am referring to.

chrome coral
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I get that. But there's no point in the extra process load when a shock cone effect can visually demonstrate just fine and is far simpler. Velocity, atmo density, and direction with a "ship slide effect" since it needs to slide forward and back down the craft depending on speed

atomic pelican
atomic pelican
atomic pelican
atomic pelican
chrome coral
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ah i understand now

atomic pelican
# chrome coral I get that. But there's no point in the extra process load when a shock cone eff...

At some point the shock cone effect would begin to fade out as the "air" becomes "too heated" (the real world causes, though here it'd be faked by reducing the volumetric effect to 0 as you approach the threshold) to condense. A little while after that the effect would begin to be emissive in the deep reds (IRL the air at these speeds begin to incandesce from compression heating), but it wouldn't become opaque at all until you reach speeds that start forming plasma. At these speeds, not only would the primary effects be focused on the bow shock and recompression shock being emissive and partially opaque, but the mixing layer itself would become emissive and take on an effect similar to shock cones in engine exhausts.

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Speaking IRL now:

Interestingly, this is the actual physical phenomenon in all regimes. It's just the shape and visibility that changes over mach values

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At lower speeds the bow shock doesn't pile up, instead being spread forward and heard as the Doppler effect. At transonic speeds, the areas of the vehicle that cause the most displacement have local areas of supersonic flow, and each of those gets it's own bow and recompression shock. If I understand it correctly the mixing layer, sandwiched between the bow and recompression shock, is the area of low pressure where condensation forms as long as the gas isn't too hot.

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At supersonic speeds, all the areas that would have caused their own local supersonic flows, still generate their own bow and recompression shocks (this is why returning spacecraft usually have two or more supersonic booms), but the effects are dominated by the primary bow and tail/recompression shocks.

atomic pelican
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Honestly I'm mostly hoping for moving away from the "fire/fur" look of the original game's reentry effects to a more impressive, accurate, and potentially more uniform and less intensive shock wave/blow torch/engine exhaust/trailing plasma, gas, and ablator sparks look which can be seen in the two videos I linked

atomic pelican
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Here's another interesting image for inspiration

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It's an image of a hypersonic test sled running along a rail. Ignore the flames starting at the back of the nose unless you're thinking about ablator material, those come from the ablative rail shoes and get trapped in the recirculation and mixing zones (and there is of course the exhaust of the SRB at the back end to deal with). You can actually see a hint of condensation in the mixing zone touching the larger cone taper, but at these speeds it's only really visible near sea level as higher altitudes don't contain enough total water vapor to overcome the heat generated in the event and condense.

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As is visible in the images at the start, blunter bodies broaden the forward point of the bow shock and push it forwards away from the object. Ablatives fill that space with outgassing ablated material to further push the bow shock forward. This is done because the area of initial compression is where the majority of the heat and plasma is generated. Said heat is actually transmitted to the object mostly via radiation instead of convection so pushing it further away reduces heating.

sacred granite
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very passionate