Reconstruction by data assimilation of the inner temperature field from   outer measurements in a thick pipe
  The detailed knowledge of the inner skin temperature behavior is very important to evaluate and manage the aging of large pipes in cooling systems. We describe here a method to obtain this information as a function of outer skin temperature measurements, in space and time. This goal is achieved by mixing fine simulations and numerical methods such as impulse response and data assimilation. Demonstration is done on loads representing extreme transient stratification or thermal shocks. From a numerical point of view, the results of the reconstruction are outstanding, with a mean accuracy of the order of less than a half percent of the temperature values of the thermal transient. 
Jean-Philippe Argaud and Bertrand Bouriquet and Aimery Assire and   St\'ephane Gervais
physics.comp-ph