The fluid flowing boundary extends outwards continuously is the feature of pressure propagation with low velocity Non Darcy percolation.

Meanwhile, the influences of pipeline internal pressure, wall thickness, crack arrest length and initial crack velocity on the crack driving force (crack propagation) are further studied.

The effects of pressure fermentation on barm propagation, the formation and reduction of diacetyl, the formation of higher alcohols and esters, and beer taste were studied in the experiments.