The Effect of groundwater level on forced convection heat transfer from a buried cylinder

The efect of groundwater level on forced convection heat transfer from a cylinder of 1 m  in diameter buried at a depth of 10 m is studied numerically. The porosity and permeability  of the soil are fxed at 0.5 and 1.0× 10–11 m2 , respectively, throughout the present study,  while the inlet velocity U0 and the position of the phreatic surface (h), measured from the  center of the cylinder, are varied in the ranges from 10–9 to 10–3 m s −1 and from − 4 to  4  m, respectively. Under these conditions, the heat fuxes on the cylinder are computed  numerically. Various approximate solutions are also proposed and compared with those  obtained numerically. The heat transfer results are also presented in nondimensional form  for generality. The paper is divided into three parts, depending on the relative positions of  the phreatic surface to the heated cylinder. First, the heat transfer rates are analyzed when  the phreatic surface is above the cylinder, so that the cylinder is completely submerged in  the water. In the second case, the phreatic surface is assumed to lie below the cylinder, so  that the cylinder is left in the water-free space. In the third case, the phreatic surface is in  contact with the cylinder surface, so that the cylinder is partially submerged in groundwater. For the above respective cases, three diferent approximate analyses are presented, and  their validities and limitations are evaluated in comparison with the numerical calculations. </p

Semi-natural habitat complexity affects abundance and movement of natural enemies in organic olive orchards

CONACyT for providing him with an international PhD student grant (registry 332659). This study was financed by the Excellence Project of the Andalusian Regional Government (AGR 1419) obtained by M. Campos and F. Ruano