I am using a user function (density changes with pressure) and using this density in the fluid properties. The simulation crashes every time I use this expression. If i don't use this expression and keep the density constant, it runs fine. I also tried checking the boxes for "Extend Min/Max", it still crashes.

Any suggestions???

could u explain me the function u used.

Be careful to remember that "Pressure" is the relative pressure, not absolute. If your function is related to the absolute pressure, use "Absolute Pressure" instead.