The correlation theory of turbulence suppression (Zhang and Mahajan 1993 Phys. FluidsB5 2000) by velocity shear was constructed by invoking the ansatz of potential vorticity conservation (PVC) that holds for relatively simple (slab) models of drift wave turbulence. It is, therefore, surprising that a detailed modern simulation of the H mode pedestal, using the gyrokinetic code GENE (Hatch et al 2018 Plasma Phys. Control. Fusion60 084003), found 'striking agreement' with the predictions of the analytic model. To understand the reasons for this remarkable agreement, an extended theory that contains finite (magnetic) curvature, and which does not conserve potential vorticity, is developed and 'solved' by calculating an inhomogeneous Green function reflecting the fact that the new system has a potential vorticity source. It is, then, demonstrated that the effect of the broken PVC is insignificant for the normal operation parameters in tokamaks; the correction due to curvature is at the order of , where is the scale length of the local gradient and is the major radius. The excellent agreement between simulation and slab model 1993 theory is therefore not accidental; the latter can be applied with confidence to the tokamak pedestal.
速度剪切抑制湍流的关联理论（Zhang and Mahajan 1993 Phys. Fluids B5 2000）是通过引入位势涡度守恒（PVC）的假设而构建的，该假设适用于漂移波湍流的相对简单（平板）模型。因此，一项使用回旋动理学代码GENE的现代H模台基详细模拟（Hatch et al 2018 Plasma Phys. Control. Fusion 60 084003）发现与该解析模型的预测“惊人一致”，这令人意外。为了理解这种显著一致性的原因，我们发展了一个包含有限（磁）曲率的扩展理论，该理论不守恒位势涡度，并通过计算非齐次格林函数来“求解”，这反映了新系统存在位势涡度源。随后证明，在托卡马克的正常运行参数下，位势涡度守恒破缺的影响可以忽略不计；由曲率引起的修正量级为 ，其中 为局域梯度尺度长度， 为主半径。因此，模拟与1993年平板模型理论之间的惊人一致并非偶然；后者可以放心地应用于托卡马克台基。