问题
单项选择题
喷口直径为400mm的圆形射流，以6m/s均匀分布的流速射出，离喷口3m处射流的质量平均流速为（）。
A．2.58m/s
B．3.58m/s
C．4.58m/s
D．5.58m/s
答案
参考答案：A
解析：
圆形射流质量平均流速沿程变化：
搜题请搜索小程序“爱下问搜题”
喷口直径为400mm的圆形射流，以6m/s均匀分布的流速射出，离喷口3m处射流的质量平均流速为（）。
A．2.58m/s
B．3.58m/s
C．4.58m/s
D．5.58m/s
参考答案：A
解析：
圆形射流质量平均流速沿程变化：
Zoe Chambers was a successful PR (Public Relations) consultant and life was going well—she had a great job, a beautiful flat and a busy social life in London. Then one evening in June last year, she received a text message telling her she was out of work. The first two weeks were the most difficult to live through." she said. "After everything I'd done for the company, they dismissed me by text! I was so angry and I just didn't feel like looking for another job. I hated everything about the city and my life." Then, Zoe received an invitation from an old school friend, Kathy, to come and stay. Kathy and her husband, Huw, had just bought a farm in north-west Wales. Zoe jumped at the chance to spend a weekend away from London, and now, ten months later, she is still on the farm. "The moment I arrived at Kathy's farm, I loved it and I knew I wanted to stay." said Zoe. "Everything about my past life suddenly seemed meaningless." Zoe has been working on the farm since October of last year and says she has no regrets. "It's a hard life, physically very tiring." she says. "In London 1 was stressed and often mentally exhausted. But this is a good, healthy tiredness. Here, all 1 need to put me in a good mood is a hot bath and one of Kathy's wonderful dinners." Zoe says she has never felt bored on the farm. Every day brings a new experience. Kathy has been leaching her how to ride a horse and she has learnt to drive a tractor. Since Christmas, she has been helping with the lambing—watching a lamb being born is unbelievable, she says, "It's one of the most moving experiences I've ever had. I could never go back to city life now." （08上海卷） 小题1:When working as a PR consultant in London, Zoe thought she lived a______life.
|