Experimental Study On The Relationship Between Roughness Of Artificial Channel And Flow Regime Of Open Channel

Basis on the artificial channel with different roughness of wall roughness coefficient, this paper does the research on the rule of open channel roughness coefficient and hydraulic elements, interrelation between every hydraulic element, influencing factors on the change of roughness coefficient using the way of combining of experimental research and theoretical analysis and makes a conclusion:(1) The Reynolds number increases with the increase of the absolute roughness of the wall surface with different roughness; the roughness coefficient has little change with increasing Reynolds number with the same kind of roughness. The effects of the Reynolds number on roughness coefficient are small.(2) When the flow is slow, the roughness coefficient only has relationship with the Froude number, that is n=f(Fr) The roughness coefficient is on the decline with the increase of Froude number. When the flow is fast, the roughness coefficient has relationship with the Froude number and absolute roughness, that is n =f(Fr, ?) The roughness coefficient increases with the increase of Froude number.(3) The Froude number increases with the increase of bottom slope in wall of different roughness. On every kind of roughness wall, when the bottom slope is steep, the changes of roughness coefficient is small with the change of the Froude number; when the bottom slope is gentle, the changes of roughness coefficient is great with the change of the Froude number. It is believed that bottom slope affects the change of the Froude number directly and affects the change of the roughness coefficient indirectly.(4) By using statistical analysis software, this paper makes a sort of 7 kinds of affecting factors that affectsthe artificial channel roughness coefficient and concludes that Froude number and absolute roughness are the factors affecting the changes of artificial channel roughness coefficient and also form regression model of different flow pattern roughness coefficient.(5) Combined with the natural river data and the physical model test results, this paper concludes that the Froude number is to become the control factor to reflect the open channel roughness coefficient and along the way resistance control.