Methods and systems for characterizing drilling fluids laden with LCM (Lost Circulation Material) and other solid materials are disclosed. A test cell for analyzing a fluid is provided with a first conical inner portion and an axial positioning device positioned along an axis of the test cell. A first conical plug is coupled to the axial positioning device and is movable in and out of the first conical inner portion along the axis of the test cell. A fluid inlet is positioned at a first location on the test cell and a fluid outlet at a second location.