Then the speed will be the same

送交者: gyro 于 2010-01-04, 14:00:31:

回答: 如果摩擦可以忽略不计－管子无流阻. 由 DW 于 2010-01-04, 13:49:42:

I guess lightman's original puzzle is simply that, when you squeeze the nozzle, the flow become faster, contradicting Bernolli's law. This law requires there is no friction and there is no vorticity. If you insist on a situation where Bernolli's law is valid, then the flow speed will be the same.

所有跟贴:

经验似乎是：堵住管子速度会变大。你的意思是这必须用粘性来解释？ - lightman (40 bytes) 2010-01-04, 14:13:59 (401015)
- I assumed friction when I talked about pressure drop - gyro (66 bytes) 2010-01-04, 14:43:53 (401019)
  - 这个快慢是因为在水管路上有比出口小的口径比如龙头开关。摩擦力不是关键 - AQuestion (162 bytes) 2010-01-04, 18:33:46 (401066)
    - 靠捏扁管子出口使流速增加好多倍是可以的 - gyro (90 bytes) 2010-01-04, 19:46:43 (401081)
    - 水龙头拧得很小时水流速变小，为什么？ (无内容) - gyro (0 bytes) 2010-01-04, 19:26:33 (401079)
      - 我上面回答了你的问题。在最小口径处速度并不小，但出口粗就小了 (无内容) - AQuestion (0 bytes) 2010-01-04, 22:46:24 (401151)
  - 多谢。 - lightman (173 bytes) 2010-01-04, 15:53:24 (401030)
- 这经验真够丰富的，连尿都尿过。 (无内容) - JFF (0 bytes) 2010-01-04, 14:25:47 (401017)

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