Following the straightening of a curved river channel at a navigation-power hub,the upstream approach channel formed a large oblique angle with the main stream,which posed significant safety risks to vessel passage.To address this issue,an integrated engineering physical model is developed to systematically investigate the navigational flow conditions in the upstream approach channel and its connecting section.Experimental results show that under the original design scheme,the transverse flow velocities in the entrance zone and connecting section of the upstream approach channel substantially exceeds the limits stipulated in relevant standards.This necessitated the implementation of engineering modifications to optimize the flow conditions.Through comparative analysis of multiple proposed schemes,the study examine the flow structures and velocity distribution patterns of the upstream approach channel and its connecting section under different intervention measures.An integrated set of measures is identified,including localized excavation,lateral repositioning of the lock,and optimization of the guidance segment geometry,length,and width of the approach channel.These modifications effectively reduce the peak transverse flow velocity from 0.61 m/s in the original scheme to 0.28 m/s,significantly enhancing the navigational flow conditions in the upstream approach channel and its connecting section,thereby improving vessel navigation safety.The methodology and findings may provide valuable reference for similar engineering projects.