Abstract: This paper presents the experimental investigation into hydrodynamicforce of two elastic circular cylinders in side by side arrangements under various gap ratiosT/D in the range of 4.19 ×10￣4 < Re < 9.1×10￣4. The steady and fluctuating pressuredistributions,steady drag and lift and fluctuating drag and lift force were obtained.Theresults show that as V_r>V_(rc),the oscillations of the cylinders affect not only the steadydrag and lift coefficients,but fluctuating drag and lift coefficients as well.There were...