Blowing a recorder at a low to moderate blowing speed with the toneholes all closed yields the lowest note in the range of the instrument. As the blowing speed is increased, the tone abruptly changes to the tone an octave higher. This “jump” in the frequency of the dominant spectral component of the tone is referred to as “regime change.” Interestingly, in conversations with recorder players, several have mentioned that regime change seems to occur at a significantly lower blowing speed for bass recorders than for instruments that sound an octave or more higher. In this paper we study regime change in the recorder and use Navier–Stokes modeling to confirm and study differences in the behavior of different instruments in the recorder family. We show, using modeling, how the regime change threshold in a model of the bass recorder can be increased by changing the geometry in the vicinity of the labium. These results are then confirmed through experimental studies of real recorders with designs inspired by the modeling results. The insights gained from these results suggest new recorder designs that may produce instruments that in some respects are more playable than current instruments.

中文翻译：

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录音机的制度变化：使用 Navier-Stokes 建模设计更好的乐器

在音孔全部关闭的情况下以低到中等的吹气速度吹奏录音机会产生乐器范围内的最低音符。随着吹气速度的增加，音调突然变为更高八度的音调。音调的主要频谱分量的频率“跳跃”被称为“状态变化”。有趣的是，在与录音机演奏者的对话中，有几个人提到，与声音八度或更高的乐器相比，低音录音机的吹气速度似乎要低得多。在本文中，我们研究了记录器中的状态变化，并使用 Navier-Stokes 模型来确认和研究记录器系列中不同仪器的行为差异。我们展示，使用建模，如何通过改变阴唇附近的几何形状来增加低音记录器模型中的状态变化阈值。然后通过对真实记录器的实验研究证实了这些结果，这些记录器的设计受建模结果启发。从这些结果中获得的见解表明，新的录音机设计可能会产生在某些方面比当前乐器更易于演奏的乐器。