Vízügyi Közlemények, 1996 (78. évfolyam)

2. füzet - Györke Olivér: Szilárd és mozgómedrű kisminták tervezés

194 Györké Olivér the case of meandering rivers with varying cross-sections along the flow the allowable distortion must be rather low. Practical experiences indicate that the allowable distortion rate is 2-fold. Distortion must not be allowed when studying three-dimensional mixing and transport processes of rivers, lakes or basins. Turbulent transport processes can be reliably modelled in Froude-models as long as the main flow remains turbulent. Consequently in these case the similarity of turbulence should as well be assured, along with that of the flow conditions. In these models the correct determination of model roughness gains special importance. A faulty design procedure is when the roughness is built into the model at the river bends, as determined from the total head loss of the surface slope using the Strickler-Manning formula, or other similar methods.