Abstract
Decreasing process of bar modes, which was found in basic experiments on plain bed and is regarded as a fundamental characteristic in formative process of multiple bars, is discussed with initial bar amplification of various modes evaluated by an existing linear stability theory. Specific features of multiple bar formation with micro scale bedforms are summarized from experiments carried out on a fine sand bed, where the mode decreasing process was also observed. Validity of the existing stability theory is examined to apply to prediction of changes in multiple bar modes on ripple-covered fine sand beds.
