After about only 70 iterations, the residuals turned to 1.#QNBe+00?
 

Hi, my friends, i am working on an magneto-hydrodynamics sonic problem, with pressure inlet and pressure_outlet boundary condition.
I used pressure-based solver with coupled method (courant Number was set to 0.01)
two UDS equations was used, and the energy equation was activated.(the under-relaxation factors was set to 0.5~0.1)

My problem is, after about only 70 iterations, the residuals turned to 1.#QNBe+00..(first the energy and UDS0, UDS1 equations, then all), i donot know why?
iter continuity x-velocity y-velocity energy uds-0 uds-1 time/iter
70 6.5896e+00 5.4005e-05 5.6830e-05 3.4253e-03 1.6723e-02 1.2403e-02 0:00:00 5
71 6.8405e+00 5.6229e-05 5.8480e-05 1.#QNBe+00 1.#QNBe+00 1.#QNBe+00 0:00:00 4
! 72 solution is converged
72 1.#QNBe+00 1.#QNBe+00 1.#QNBe+00 1.#QNBe+00 1.#QNBe+00 1.#QNBe+00 0:00:00 3