Yes, you are correct Bagas in your understanding of the differences between the inviscid and viscous models. In the inviscid model, the fluid viscosity and friction are ignored, which results in a flow that is more symmetrical and without boundary layers. However, this can also lead to instabilities in the flow.
On the other hand, in the viscous model, the effects of fluid viscosity and friction are taken into account, resulting in a more stable flow. This is because the viscosity and friction help to dampen out instabilities in the flow.
In general, the choice of model depends on the specific problem you are trying to solve. If the flow is expected to be relatively simple and symmetrical, the inviscid model may be sufficient. However, if the flow is more complex or if stability is a concern, the viscous model may be necessary.
It’s also worth noting that the choice of numerical method used to solve the equations can also have an impact on the stability of the solution. Some numerical methods may be more prone to numerical instabilities than others, and the choice of method should be carefully considered based on the specific problem being solved.