New chiral mesogens 3(R)-methylcyclohexanone derivatives

New chiral compounds 3R-methylcyclohexanone derivatives were synthesized. These compounds were revealed to exhibit the mesomorphic behavior within rather wide temperature ranges. Types of formed mesophases and phase transition temperatures were determined by polarizing microscopy, differential scanning calorimetry and small angle scattering of X-ray. Mesomorphic properties of the new chiral compounds were compared with those for the chiral 2-arylidene derivatives of 3R,6R-3-methyl-6-isopropylcyclohexanone (d-isomenthone) studied earlier. Distinctions between these two types of compounds in an ability to form mesophases and also in twisting properties as chiral dopants in induced cholesteric mesophases are considered.

Off-wall boundary conditions for turbulent flows obtained from buffer-layer minimal flow units

There is strong evidence that the transport processes in the buffer region of wall-bounded turbulence are common across various flow configurations, even in the embryonic turbulence in transition (Park et al., Phys. Fl. 24). We use this premise to develop off-wall boundary conditions for turbulent simulations. Boundary conditions are constructed from DNS databases using periodic minimal flow units and reduced order modeling. The DNS data was taken from a channel at Reτ=400 and a zero-pressure gradient transitional boundary layer (Sayadi et al., submitted to J. Fluid Mech.). Both types of boundary conditions were first tested on a DNS of the core of the channel flow with the aim of extending their application to LES and to spatially evolving flows.