Help please - Wind tunnel Scale models

[F18405]

Most teams in F1 now use 60% scale models in there wind tunnels but all there designs are done to full scale. So can some please tell me what formula's would be used to convert a model from full scale to 60%? how do they calculate the volume of the model at 60% and also if they are using 60% models how to they calculate the air speed required for the model in the wind tunnel? I know this may be simple to most but my maths are not brilliant.

Cheers

[volarchico]

The scaling to create the model itself is pretty simple. All length measurements are multiplied by 0.60.

For wind tunnel speed, Reynolds number matching is the usual method of determining the speed to match the full scale version.

Re=rho*V*L/mu

Ignore rho and mu for simplicity and you have an inversely proportional relationship for V (velocity) and L (some characteristic length, such as the length of the car). So if the length goes down to 60%, then the velocity must increase by an equivalent amount.