Flow uniformity is an important index in many research fields.In order to use directly numerical simulation results to analyze flow uniformity quickly

abolish the data collection points setting and simplify computation process

a new correlation based on area-weighted and mass-weighted average velocity was proposed through the uniformity analysis of 24 velocity distribution under the circumstance of three velocity change at assumed cross-section in this study.The correlation and the corresponding formula in the literature were respectively adopted to calculate the uniformity of 24 velocity distribution at assumed cross-section.The results showed that the evaluating results by the correlation were basically consistent with that by the formula when velocity distribution uniformity was over 60%

the evaluating results by the correlation were worse than that by the formula when velocity distribution uniformity was less than 60%.However

the flow that uniformity is worse always need to further improve its structure

the uniformity was just providing a basis for improvement.Therefore

the results by the correlation have fully reference value for analysing flow uniformity.Finally

take supplying air of a metro vehicle air-conditioning duct as an example

the above theoretical analysis results were further verified

which confirmed the rationality of the correlation reflecting flow uniformity.