• When the speed falls below this level, ...
• The shock waves slow down ( or are retarded ) appreciably as they progress along the tube.
• When the speed falls below this level, ...
• The shock waves slow down ( or are retarded ) appreciably as they progress along the tube.
Циммерман М., Веденеева К.. Русско-Английский научно-технический словарь переводчика. Russian-English scientific dictionary for translators. 2012