Holen J, Waag R C, Gramiak R, Violante M R, Roe S A
Ultrasound Med Biol. 1985 Mar-Apr;11(2):261-6. doi: 10.1016/0301-5629(85)90124-3.
The validity of an orifice equation (Torricelli's law) which expresses a simple relationship between the pressure difference across an orifice and the maximum fluid velocity in the orifice was tested in vitro. An aqueous suspension of barium sulfate particles with a polymer added to attain variations in viscosity, was forced through orifices which ranged in diameter from 0.4 to 4.7 mm. The pressure difference across the orifice was determined with a transducer and the maximum fluid velocity in the orifice was determined with Doppler ultrasound. Tests were performed at Reynolds numbers, fluid viscosities, and pressure differences that spanned the following ranges: 400-25,000, 1-5 cP, and 3-100 mmHg, respectively. At pressure differences larger than 3 mmHg and fluid viscosity 3 cP (approximate viscosity of in vivo blood), Torricelli's law was demonstrated to be valid for orifice diameters larger than 1.6 mm. The validity of the law was found to be relatively insensitive to variations in orifice length.
一个表达孔口两端压力差与孔口处最大流体速度之间简单关系的孔口方程（托里拆利定律）在体外进行了验证。添加了聚合物以实现粘度变化的硫酸钡颗粒水悬浮液被压过直径范围为0.4至4.7毫米的孔口。孔口两端的压力差用传感器测定，孔口处的最大流体速度用多普勒超声测定。测试在雷诺数、流体粘度和压力差分别跨越以下范围的条件下进行：400 - 25000、1 - 5厘泊和3 - 100毫米汞柱。在压力差大于3毫米汞柱且流体粘度为3厘泊（体内血液的近似粘度）时，托里拆利定律被证明对于直径大于1.6毫米的孔口是有效的。该定律的有效性被发现对孔口长度的变化相对不敏感。
