A.1米,λQ=1000 B.10米,λQ=100 C.1米,λQ=100000 D.10米,λQ=100000
A.1.54m/s B.2.0m/s C.2.45m/s D.3.22m/s
A.K/d B.Re C.Re和K/d D.管內(nèi)壓強(qiáng)