【摘要】 现行工程流体力学与水力学理论通常认为粘性流体元流伯努利方程中的水头损失项是恒正的,并且这部分损失的机械能转变为热而耗散掉了。这种解释是错误的。该错误不仅导致了粘性流体元流伯努利方程在现行解释下不再成立,而且导致了从粘性流体元流伯努利方程出发来推导粘体流体总流伯努利方程的推导方法丧失了理论基础。直接从纳维斯托克斯方程出发,推出粘性流体总流伯努利方程,该方法不仅给出了一种新的推导粘性流体总流伯努利方程的途径,而且通过推导过程给出了更明确、更严格的应用粘性流体总流伯努利方程的条件。更多还原

【Abstract】 According to current engineering hydrodynamics, there’s positively constant head loss in Bernoulli’s theorem for identical stream line in viscous fluid, which can later turn into heat and dissipate. This concept is proved to be incorrect. Because of this error, the current interpretation of Bernoulli’s theorem for identical stream line in viscous fluid can no longer exist. What’s more, the deducing process of Bernoulli’s theorem for main stream line in viscous fluid based on that for identical stream line loses its foundation. Bernoulli’s theorem for main stream line in viscous fluid is deduced directly on the basis of Navier-Stokes equation. The suggested deducing process can not only be a new approach to the foundation of Bernoulli’s theorem for main stream line in viscous fluid, but also provide clearer and more precise rules for the application of it.更多还原