So, if your business goes belly up, you lose your money you go bankrupt.

如果你“肚子朝上”，你失去了你的钱，你破产了。

If a project you're doing goes belly-up, it just goes badly wrong. So, it goes belly up.

如果你正在做的一个项目“肚子朝上”，它就出现了严重的错误。因此它失败了。