The curved surface of internal contraction tunnel of two-dimensional hypersonic inlet was designed and investigated.Based on hypersonic inlet with the same internal contraction area ratio and throat area

the influences of the length of internal contraction tunnel and the tension of the shoulder spline on the inlet performance were studied numerically.Results indicate that the length of internal contraction tunnel has great effect on the total pressure recovery coefficient and the starting-up Mach number.When the length to throat height ratio is 8.4

the total pressure recovery coefficient is better.Spline with suitable tension to replace the traditional surface with radii at shoulder can increase the total pressure recovery coefficient.With the increase of the length of internal contraction tunnel

the corresponding optimal tension of spline will decrease.The recommended range of spline tension is 0.80-1.25.