A server rack door has a first dimension and a second dimension orthogonal to the first dimension and includes a first group of first obstructions arranged along the first dimension. The first obstructions define a first plurality of flow channels. The server rack door further includes a second group including second obstructions arranged along the first dimension and offset from the first obstructions along the second dimension. The second dimension corresponds to a thickness of the server rack door. The second obstructions define a second plurality of flow channels, where the first obstructions and the second obstructions alternate along the first dimension.