# NAMGRD=CONV. compressible calculations

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 August 22, 2003, 09:19 NAMGRD=CONV. compressible calculations #1 yann Guest   Posts: n/a hi, i have to make compressible calculation in BFC, with shocks, transonic flow... in several case library, the option NAMGRD=CONV is used in conjunction with UCONV=T ... i understand UCONV=T is used to say that higher order scheme will be used , but what is the effect of NAMGRD=CONV , and should these 2 options work together and should be used together?? also, it is not clear, in documentation and examples, what is the energy formulation to be used for such calculation, mainly the problem is i cannot see the exact partial equation for eaach case... do u know what is the best formulation and why? finally, i never find an example with correct boudary conditions: normally they should change following iterations: for a nozzle, for instance, the mass flow rate is not know a priori and the shoking or non-shoking of the nozzle should be computed. so total values should be prescribed (generally known) and mass flow rate should be computed from solution in fly: it can be done by giving a mass flow rate condition (with scalar P1) but C and V calculated in ground: C= (2*gamma)/(W1*(gamma-1)) W1 at current iteration V= (Po*RHO1)/(RHO_o) with RHO1 at current iteration the condition for W1 is COVAL(in,W1,ONLYMS,SAME) for those who are interested, it works well. but problems arise when energy is added. i thought to solve static enthalpy and prescribe for it a fixed value (in ground): h1 = CP*To -0.5(W1)**2 with W1 at current iteration and in conjunction with the perfect gas law in this way stagnation values are all given:Po, To, RHO_0 but the coupling involve some problems , do you know how to deal with the energy equation