This paper reports the pressure drop through a monolith for turbulent and laminar flow. A computational model of a monolith channel together with the open sections before and after it is used. Simulations at several channel Reynolds numbers, and assuming laminar and turbulent flow approaching the substrate are considered. Reynolds average Navier Stokes (RANS) and large eddy simulation (LES) are used as flow models in the cases with turbulence. The resulting pressure drop, power spectrum and flow regime are analysed. RANS predicts a decay of the turbulence as the flow approaches the substrate, a small fraction of the turbulence effectively entering the channels to decay rapidly, then steady flow from that point. On the other hand, LES predicts a total dissipation of the turbulence before the flow enters the channels; however, the flow remains unsteady along the entire substrate, in a sort of pulsating regime. Despite the significant differences in the flow regime, both models predict a marginal influence of the upstream turbulence on the total pressure drop. The dominating frequencies of the pulsating flow inside the channels were found to be comparable to the ratio of the channel velocity over the channel diameter, therefore, to the channel Reynolds number.

本文报道了通过整体的湍流和层流的压降。整体通道的计算模型以及使用之前和之后的开放部分。考虑在多个通道雷诺数下的模拟，并假设层流和湍流接近基底。雷诺平均湍流（RANS）和大涡模拟（LES）被用作湍流情况下的流动模型。分析所得的压降，功率谱和流动状态。RANS预测湍流将随着流向底物而衰减，一小部分湍流有效进入通道以迅速衰减，然后从该点开始稳定流。另一方面，LES预测在流体进入通道之前湍流的总耗散。然而，在某种脉动状态下，流动沿整个基底保持不稳定。尽管流动状态存在显着差异，但这两个模型都预测了上游湍流对总压降的边际影响。发现通道内部的脉动流的主导频率与通道速度在通道直径上的比率可比，从而与通道雷诺数相当。