Complex pressures must be applied with a surface effect element (surf154). In Mechanical you can use APDL commands to create surf154 elements on a face and input the real and imaginary pressure tables. If the pressure is frequency dependent and also varying along a direction then the pressure table rows should be corresponding to frequency and columns should be corresponding to directional position(X\/Y\/Z) if any. The first row and first column in the text files should be used for indexing therefore should not have pressure data. In the data file, first column should have corresponding frequency values and first row should have directional position values. The first row and first column used as index numbers are stored in zero row and zero column in APDL table. The index values should be in ascending order. Following is an example where text files for real and imaginary pressure values are imported into Mechancial using command snippet. The pressure is frequency dependent and also varies along the X direction. The input text files preal.txt, pimag.txt and Xlength.txt are copied to Mechanical project’s solver directory.<\/p>\n