Joint scalar pdf

As observed in previous DNS calculations, ignition occurs at a "most reactive" mixture fraction. The present calculations indicated that turbulence intensity had little effect on ignition temperatures, which were about 30 K higher than, but parallel to, laminar ignition temperatures.

Similar results were found for both the IEM and modified Curl's mixing model. Turbulent ignition temperatures were similar to laminar ones when the mixing model was modified to account for preferential diffusion. These results are different from turbulent ignition experiments since the experiments did indicate a turbulent intensity effect on ignition of up to 35 K.

These discrepancies were attributed to shortcomings in the molecular mixing models in the flows of interest where the turbulent Reynolds numbers are low. A potential source of this problem was identified as the representation of the scalar mixing frequency as a constant ratio of the scalar to flow time.

A joint scalar PDF study of nonpremixed hydrogen ignition. N1 - Funding Information: It is a pleasure to acknowledge the support of the present research by the Army Research Office under the technical monitoring of Dr.

N2 - A two-step process was adopted to model turbulent ignition that takes advantage of the possibility of decoupling the mechanical flow from chemical reaction due to the small amount of heat release before ignition. AB - A two-step process was adopted to model turbulent ignition that takes advantage of the possibility of decoupling the mechanical flow from chemical reaction due to the small amount of heat release before ignition.

Overview Fingerprint. Abstract A two-step process was adopted to model turbulent ignition that takes advantage of the possibility of decoupling the mechanical flow from chemical reaction due to the small amount of heat release before ignition.

Access to Document Link to publication in Scopus. In principle, the JVSPDF simulations can be closer to physical reality, as a differential model is implied for the scalar fluxes, whereas the gradient diffusion hypothesis is implied in JSPDF simulations. In the neck zone, where the turbulent flow field results deteriorate, the joint scalar PDF results are in somewhat better agreement with experimental data, for the test cases considered.

In composition space, where results are reported as scatter plots, differences between the two PDF strategies are small in the calculations at hand, with a little more local extinction in the joint scalar PDF results. This is a preview of subscription content, access via your institution.

Rent this article via DeepDyve. Pope, S. Ren, Z. Article Google Scholar. Merci, B. Dally, B. Theory Mod. Cao, R. Liu, K. Gkagkas, K. In: Roekaerts, D. Delft, , pp. Lindstedt, R. Barlow, R. Sreedhara, S. Bykov, V. Warnatz, J. Springer [ISBN]. Nafe, J. Li, G. Flow, Turbul. Janicka, J.

Subramaniam, S. Naud, B. Muradoglu, M. Jenny, P. AIAA J. Launder, B.