Triple bars (e)

The next configurations consists of three vertical bars of $0.75h$ height and a spacing of $0.7h$. The results obtained for this geometry show damping of the lift fluctuations similar to the twin bar configuration but a negative effect on the mean drag ($+12\%$). As the main difference to the last case is that the relative sizes of the bars is equal, this feature seems to have an important impact on the mean drag.

It can be concluded that for damping the lift fluctuations, it is essential to allow contact between the top and bottom sides of the Gurney (twin/triple bars). For drag reduction however, it is more important to damp the flow structures or to reduce their size (splitter-plate/twin bars) which is facilitated by the relationship between the bar heights in the twin bar case. With the next configuration an attempt is made to combine these to features.