In typical city traffic situations the additionally to the radar measurement even the lateral velocity component of each detected target such as a vehicle is of large interest.

Aiming at the two question:dual-beam laser Doppler velocimeter can not measure the velocity out of focus and the running road surface of the ground navigation system fluctuates usually,the paper put forward and designed the reference-beam laser doppler velocimeter to measure the transverse velocity of moving surface.

In allusion to the basic characteristic of residential building\'s atrium space and the prodecessors\' study result,the article takes the transverse current which enters the atrium in the landscape orientation as the main studying object and adopts a simulation software of CFD called Fluent to simulate and analyse the factors which affect the ventilatiuon of the atrium.

It is believed that the main cause resulted in tube breakage in said heat exchanger is the vibration of tubes in the heat exchanger due to the horizontal flow speed of closed-loop cooling water at inlet and outlet of the heat-exchanger being larger than the critical speed.