Precise evaluation of flame surface area plays a pivotal role in the fundamental understanding and accurate modelling of turbulent premixed flames. This necessity is reflected in the requirement for the instantaneous flame area evaluation of the turbulent burning velocity (by making use of Damköhler’s first hypothesis). Moreover, the information regarding flame area is required in the context of flame surface density based modelling, and for determining the wrinkling factor or estimating the efficiency function. Usually flame surface areas in experiments and Direct Numerical Simulation (DNS) analyses are evaluated differently and the present analysis aims at comparing these approaches by making use of a detailed chemistry DNS database of turbulent, statistically planar flames. It has been found that the flame surface area evaluation is sensitive to the choice of scalar quantity and the isosurface level, and this holds particularly true for two-dimensional evaluations. The conditions, which provide a satisfactory agreement between experimental and numerical approaches in the flame area evaluation, have been identified by a detailed comparative analysis of the usual postprocessing techniques.

中文翻译：

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基于不同燃烧状态预混湍流氢气-空气火焰详细化学DNS的火焰面积评价

火焰表面积的精确评估在湍流预混火焰的基本理解和准确建模中起着关键作用。这种必要性反映在对湍流燃烧速度的瞬时火焰面积评估的要求中（通过使用 Damköhler 的第一个假设）。此外，在基于火焰表面密度的建模以及确定起皱因子或估计效率函数的背景下，需要有关火焰面积的信息。通常对实验和直接数值模拟 (DNS) 分析中的火焰表面积进行不同的评估，本分析旨在通过利用湍流、统计平面火焰的详细化学 DNS 数据库来比较这些方法。已经发现火焰表面积评估对标量和等值面水平的选择很敏感，这对于二维评估尤其如此。通过对常用后处理技术的详细比较分析，确定了在火焰面积评估中实验方法和数值方法之间具有令人满意的一致性的条件。