Timeline for How does a weak shock-wave boundary-layer interaction create wave drag (other than through direct shock losses)?
Current License: CC BY-SA 4.0
6 events
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| Jan 16, 2019 at 16:34 | comment | added | Felix L. | Yes, static pressure increases across the shock wave. But in contrast to subsonic flow, supersonic flow accelerates when it expands.This is what happens after the thickest point. The static pressure decreases with flow acceleration. This is why you have an area of reduced pressure beyond the thickest point. Because of the total pressure loss, static pressure is even lower than how it would have been without the shock, if that makes sense. | |
| Jan 13, 2019 at 10:42 | vote | accept | Daniel | ||
| Jan 13, 2019 at 10:42 | comment | added | Daniel | Alright, but the static pressure still increases across the shock wave, right? So intuitively I would think that this increased static pressure provides some "pressure thrust", if it acts after the thickest point. | |
| Jan 12, 2019 at 21:44 | comment | added | Felix L. | Exactly. The increased turbulence in the BL should be the main cause for increased friction drag. However, total-pressure loss across the shockwave always plays a role for drag. How much either effect contributes to shock-induced drag will greatly depend on the flow in each specific situation. Intuitively I would expect the total-pressure loss to be the stronger effect in most cases. | |
| Jan 7, 2019 at 12:29 | comment | added | Daniel | Great, thank you for the detailed answer! So, to summarise, the increase in drag due to a weak shockwave would be because of an increased turbulence in the BL after the shockwave (therefore friction drag)? I guess that the increase in pressure drag due to the lack of pressure recovery after the thickest point (see comment on my qeustion) also plays a role although that is only correlated to the presence of shock waves, and not caused by. | |
| Jan 7, 2019 at 10:17 | history | answered | Felix L. | CC BY-SA 4.0 |