Experimental simulation of alternating aerodynamic load induced by
tunnel passing of high-speed train
Abstract
Tunnel passing in high speed produces aerodynamic load on railway train,
which brings about fatigue failure on the car-body, and damages
passenger comfort due to interior penetration of the alternating wave.
Experimental simulation of the alternating load remains a challenge
concerning its accuracy and reliability. In this work, experiment
approaches in terms of air compression and air suction were developed,
in an attempt to simulate the air pressure variation when the train runs
through tunnels. Pros and cons of the introduced methods were analyzed
by theoretical calculation and numerical simulation, and further
validated in experimental tests. It is revealed that in air compression
means of eccentric wheel and stepping motor propulsion, pressure
amplitude in simulation both exceeds that in theoretical calculation due
to temperature change from piston movement. The deviation between tests
and theoretical values climbs up as the pressure wave cycle rises. The
stepping motor propulsion is recommended in scaled simulation for human
ear comfort because of its equal peak and valley span, but suggests
insufficient engineering feasibility in full size vehicle tests.
However, the air suction performs excellently through internal and
external loading utilizing the valve controlling strategies. By
simulating the pressure wave obtained from in-transit vehicle tests, the
relative deviation of the extremes between simulation and vehicle tests
is within 5.0%. Research outcome indicates that the proposed method
provides an important experiment means for passenger comfort and
car-body fatigue behavior research.