Continuity residual problem
 

Hello guys,
I am running unsteady calculation. I am trying to simulate a natural convection problem.
Any body knows why there is variance in my continuity residual in each time step ?

453199 3.9771e-02 50
453200 6.3894e-02 49
453201 8.1138e-02 48
453202 6.3596e-02 47
453203 5.0609e-02 46
453204 4.0559e-02 45
453205 4.7478e-02 44
453206 4.6637e-02 43
453207 4.0542e-02 42
453208 4.2918e-02 41
453209 4.2985e-02 40
453210 5.7021e-02 39
453211 4.6841e-02 38
453212 4.4078e-02 37
453213 4.1917e-02 36
453214 4.7714e-02 35
453215 3.6663e-02 34
453216 5.0971e-02 33
453217 5.1721e-02 32
453218 6.7693e-02 31
453219 3.7119e-02 30
453220 3.3932e-02 29
453221 5.8835e-02 28
453222 5.5083e-02 27
453223 4.3667e-02 26
453224 4.1806e-02 25
453225 4.1960e-02 24
453226 4.6105e-02 23
453227 3.9779e-02 22
453228 4.5177e-02 21
453229 4.2945e-02 20
453230 5.7722e-02 19
453231 4.6159e-02 18
453232 4.2947e-02 17
453233 4.1472e-02 16
453234 4.7435e-02 15
iter continuity time/iter


Thank you,
Hooman