CFD Online Discussion Forums

CFD Online Discussion Forums (
-   FLUENT (
-   -   Floating point error:invalid number (

zhaopeng March 24, 2009 06:55

Floating point error:invalid number
there is an cube submerged in water,its interior is also filled with water.the outlet is on the cube's bottom,the inlet connected to a air compressor is on the cube's object is to obtain how long can the water in the cube be evacuated.but when I start iterate,it show that "Floating point error:invalid number".can anyone help me? thanks in advance.

The solve settings are as follow:

Version: 3d, pbns, vof, ske, unsteady (3d, pressure-based, VOF, standard k-epsilon, unsteady)
Release: 6.3.26
Model Settings
Space 3D
Time Unsteady, 1st-Order Implicit
Viscous Standard k-epsilon turbulence model
Wall Treatment Standard Wall Functions
Boundary Conditions
name id type
fluid 2 fluid
wall 3 wall
outlet 4 pressure-outlet [Gauge Pressure=50662Pa,Backflow Volume Fraction(water)=0]
inlet 5 mass-flow-inlet [Supersonic/Initial Gauge Pressure=202650Pa,Mass Flow-Rate(air)=0.01Kg/s,Mass Flow-Rate(water)=0 Kg/s]
default-interior 7 interior
Pressure-Velocity Coupling
Parameter Value
Skewness-Neighbour Coupling yes
Skewness Correction 1
Neighbour Correction 1
Discretization Scheme
Variable Scheme
Pressure Body Force Weighted
Momentum First Order Upwind
Volume Fraction Geo-Reconstruct
Turbulent Kinetic Energy First Order Upwind
Turbulent Dissipation Rate First Order Upwind

martingariepy March 25, 2009 19:59

Hi there,

Usually, this is due to a division per zero. A common exemple arrive when in you're reference panel, you set reference velocity to zero and you try to compute drag coefficient. You then got that type of error. Another common exemple is when you're using ideal law but you're operating pressure is set to zero!.

Best regards


zhaopeng March 26, 2009 02:01

Thanks for your reply.
I have already examined the model settings and boundary conditions.The same model setting and boundary condition in 2D case do not result in similar problem,although the final result may be wrong. while they are used in 3D case,Fluent shows that "Floating point error:invalid number".

By the way,is mass flow inlet boundary applicable for the outlet of air compressor?Usually we konw the air delivery(L/min) and air pressure(PSI) of an air compressor.

All times are GMT -4. The time now is 11:00.