The way this effect works, however, is dependent on a Coriolis-force-induced veer in the atmospheric boundary layer, something that is not an issue in contra-rotating propellers. Unless one understands the mechanism, one will be unaware that, for any given location, it matters which way the first turbine rotates. At best, an arrangement based on an analogy to contra-rotating propellers would be a lucky guess, right for the wrong reasons.