A method of assessing a membrane, including calculating fluid dynamic characteristics of at least one of a membrane and a material to be passed through the membrane, where the material comprises particles; obtaining characteristic of at least one force acting on the particles of the material to be passed through the membrane due to the interaction between the particles and the membrane, the at least one force being an intermolecular force; combining the calculated fluid dynamic characteristic and the obtained characteristics to assess the flow of the material through the membrane; and optimizing at least one characteristics of the membrane in relation to the material. The membrane includes a plurality of rows and a plurality of teardrop structures arranged in the plurality of rows. The teardrop structures in each row are arranged at substantially the same angle with respect to an anticipated direction of flow through the membrane.