A few definitions
Filling sand castings. Basic concepts

The most common system types include :

• a funnel or pouring basin;

• a vertical downspout with cross-sectional area S _d ;

• a horizontal duct, known as the pouring channel, with cross-section S _c upstream of the first attack, distributing the metal flow into the cavity via small ducts, known as attacks, whose total cross-section is S _a .

Depending on whether the sequence of relative values of the cross-sections S _d , S _c and S _a is increasing or decreasing, it is common practice...