The experimentaI results 〔 }f the ch 〔, king pressure ratio and the choked 日ow rate in u c nverging nezzle are con / pared with three theoretical values calculated by the Fanno 且 w theory , the compound fioLv mode1 , and thc average now rn 〔 〕deL The experiment . atvalues are in qualita 亡 ive agreenler ユt with the calculated va ] ues in any of these cases , and agree best with the 、 ・ alucs by し he average 飾 w m σde1 . Based upon thcse compar 孟 sons , the mechanism of the choking of the flow where し he velocity distTibutic 〕ll is n { 〕t uniform due to the beundary 】 ayer is rnade dear ,