Application of Quadratic Constitutive Relation to One- Equation k-kL Turbulence Model

This paper analyzes the accuracy of the recently developed one-equation k-kL turbulence model with Quadratic Constitutive Relation (QCR) compared to the linear Boussinesq relation and Algebraic Reynolds Stress Model (ARSM). The computational results in several benchmark cases from NASA TMR are compared to other widely used one equation turbulence models with QCR, such as Spalart-Allmaras model (SA), Wray-Agarwal model (WA) and SST k-ω model. In particular, one-equation k-kL-QCR model shows good accuracy with experimental data for supersonic flow in a square duct where the effect of QCR is clearly visible in capturing the secondary flow vortices which is not feasible with the any standard model without QCR. In addition, both one-equation k-kL and one-equation k- kL-QCR models show better accuracy for subsonic separated flow in 3D NASA Glenn S- duct compared to other one-equation models. Other test cases show little difference in the results obtained without and with QCR

δ15N value does not reflect fasting in mysticetes.

The finding that tissue δ15N values increase with protein catabolism has led researchers to apply this value to gauge nutritive condition in vertebrates. However, its application to marine mammals has in most occasions failed. We investigated the relationship between δ15N values and the fattening/fasting cycle in a model species, the fin whale, a migratory capital breeder that experiences severe seasonal variation in body condition. We analyzed two tissues providing complementary insights: one with isotopic turnover (muscle) and one that keeps a permanent record of variations in isotopic values (baleen plates). In both tissues δ15N values increased with intensive feeding but decreased with fasting, thus contradicting the pattern previously anticipated. The apparent inconsistency during fasting is explained by the fact that a) individuals migrate between different isotopic isoscapes, b) starvation may not trigger significant negative nitrogen balance, and c) excretion drops and elimination of 15N-depleted urine is minimized. Conversely, when intensive feeding is resumed in the northern grounds, protein anabolism and excretion start again, triggering 15N enrichment. It can be concluded that in whales and other mammals that accrue massive depots of lipids as energetic reserves and which have limited access to drinking water, the δ15N value is not affected by fasting and therefore cannot be used as an indicatior of nutritive condition