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Traditionally woodwind makers use holes with undercuts for many reasons. First of all, when the instrument is crafted, it iseasier to round the hole inner edge than change its place to correct the tuning. In the case of the development of a numericaloptimization heuristic, known analytical model don’t take into account undercutting in holes, so that they often simply consider adual cylinder connection. For this specific geometry a turbulent flow layer effect has already a prominent dissipative action, evenfor a low excitation pressure equivalent to a piano musical dynamics.